For the Ghostbusters of Legacy Systems

👻 Over-customization isn’t clever — it builds a haunted castle of untouchable code.

🧟 Legacy customizations never truly die — zombie programs stagger on long after their purpose.

🧪 All those patches aren’t a badge of honor — they turn you into Dr. Frankenstein with a laptop.

🧹 Clean Core isn’t just a technical strategy — it’s a cultural reset (a rebellion against complexity).

🌟 S/4HANA migration isn’t just an upgrade — it’s a once-in-a-generation chance to start fresh.

If you’ve ever opened an SAP system and felt like you were stepping into a haunted castle of custom code, this conversation is for you. It’s for the seasoned SAP freelancers and consultants who’ve made a living navigating Frankenstein systems and zombie programs, yet secretly dream of a simpler, cleaner way. We know that paradox all too well: the very expertise that made you invaluable (untangling decades-old ABAP spells and keeping monsters alive) can also feel like a curse chaining you to endless maintenance. And guess what? You don’t have to be the gravedigger for old code forever. Not in the age of S/4HANA, where a clean slate isn’t a fantasy—it’s a strategic choice.

Why read on? Because in the dialogue that follows between Isard (a veteran SAP freelancer turned aspiring entrepreneur, battle-hardened in the old ways) and his AI sidekick Wiz (wry as ever, with wisdom served in riddles), we uncover how mastering a Clean Core approach can flip the script of your career. By the end, you’ll walk away with:

• A fresh perspective on Clean Core: an understanding of it as a mindset shift and cultural revolution, not just another technical best-practice.
• A challenge to test your limits with standard SAP: inspiration (and some tactical tips) to see how far you can go without writing a single line of custom code – and why that’s so powerful.
• An entrepreneurial game plan: insight into turning the ability to configure a working S/4HANA system in one day into a marketable offering that sets you apart in this new era.

Sound good? Excellent. Pour yourself a coffee (or something stronger if you’re still exorcising last project’s demons), and listen in on this winding, witty, and eye-opening conversation. It might just inspire you to trade in your old bag of custom tricks for a clean slate – and start rewriting your professional story in the process.

(Late on a Saturday morning, Isard sits in his home office, sunlight catching motes of dust above a desk cluttered with old project binders and a freshly made tea. On his screen: a brand-new S/4HANA trial system, pristine as a medieval scroll waiting for ink. Wiz, an AI mentor visible only to Isard, hovers just above the monitor – today, he’s sporting a metaphorical Ghostbuster logo on his translucent jacket. The atmosphere is equal parts nostalgia and excitement, like an old warlock flipping through a new spellbook.)

Ghosts in the Code – The Curse of Customization

Isard: staring at the blank SAP screen You know, Wiz, sitting here with this clean system in front of me… I can’t help but remember the haunted ones I’ve dealt with. Decades of layers, custom on top of custom – some of that code was so old and twisted it practically groaned when you logged in.

Wiz: raises an eyebrow, smirking Ah yes, story time. Let me guess: you’re thinking about that ECC system you called “the haunted castle” once? The one crawling with ghost transactions and zombie code that no living soul dared touch?

Isard: chuckles Bingo. That client’s system was a legend – or a horror story. Everyone on the project whispered about it like an ancient curse. There was this one ABAP report – written in the late 90s, patched in ’05, mutated in ’13 – by then it was so critical and so fragile that people treated it like a sleeping dragon. We even joked it had a “Here Be Dragons” comment in the code. No one wanted to be the knight who poked it and woke it up.

Wiz: grins A dragon in the code castle. Did it breathe fire or just dump core?

Isard: Maybe both. It controlled pricing, taxes, some convoluted workflow – and naturally, the original dev was long gone, the documentation was… nonexistent, and every attempt to change it had failed spectacularly. They had bug fixes for the bug fixes. It was literally undead code – not alive, not maintainable, but not dead either. One might say it was zombie code, shambling along release after release, feasting on IT budgets.

Wiz: feigned dramatic shiver Gives me the chills. Though, you have to admit, part of you got a thrill from it back then. A twisted pride in being one of the few who could navigate that graveyard without running away screaming.

Isard: Guilty. It’s weird, isn’t it? We freelancers often become the ghostbusters of these legacy systems. They call us in when the house is already haunted: “Come in, neutralize this poltergeist of a program, and by the way, don’t break anything.” I spent years playing that hero role – slinging custom code like a proton pack, catching one ghost only to find another lurking behind it.

Wiz: And carrying a Frankenstein laptop full of special tools to do it, no doubt. Remember when your poor ThinkPad had five different VPN clients, three SAP GUI versions, custom scripts for each client, plus that weird Java applet one customer needed for their bespoke interface? It was like your laptop had bolts sticking out of the sides.

Isard: laughs Oh, I remember. That machine was a monster in its own right – my own little patchwork creation to interface with all the monsters I had to tame. I used to joke I needed an exorcist for my hard drive. By Friday nights, it certainly felt possessed.

Wiz: So here you are now, staring at a virginal S/4HANA system. No ghosts, no monsters. Just a clean quiet castle waiting for life. What’s running through your head? Regret that most systems aren’t this pristine? Relief that you’re not dealing with any “ghost code” today?

Isard: Honestly… a bit of awe. Awe at how clean it is. Everything’s standard, as SAP intended. It’s beautiful, really – like freshly fallen snow on a field, no footsteps yet. And I’m thinking: all those years, I was basically a janitor in a decrepit mansion, sweeping up bat droppings and patching cracks in the walls. What if, instead, I could be an architect building something new on an open field?

Wiz: softly, with a hint of pride That, my friend, sounds like the beginning of a realization. Careful – you’re on the verge of a profound metaphor.

Isard: smiles, eyes distant I mean, look – I’ve seen what over-customization does. It’s seductive at first: “Sure, we can tweak that, we can build you exactly what you want.” But 10 years later, you have a labyrinth no one can navigate, not even the minotaur that lives in there. Clients don’t own a flexible system; they own a creature they fear. I’ve felt that fear in their voices: “Don’t change that, we don’t know what will happen… The guy who built it retired… We just live with the quirk.” It’s like living in a castle with haunted hallways you avoid instead of fixing the damn wiring.

Wiz: Meanwhile, every new consultant they bring in – present company included – ends up roaming those halls with a lantern and a nervous prayer, hoping not to disturb the wrong spirit.

Isard: Exactly. And I realize now, I don’t want to be that ghostbuster forever. I don’t want my value to be measured by how well I can fight fires or placate vengeful code-spirits. At some point, I want to say: let’s tear this haunted house down and build something clean. Something we’re not afraid of.

Wiz: leans forward, the ghostbuster logo on his jacket dissolving into a simple lightbulb icon Enter Clean Core, stage right. The promise of a house with no ghosts, eh? Or at least a rule that we won’t create any new ones. Let’s talk about that – because I suspect this shiny new S/4 system on your screen is more than a hobby to you. It’s a statement.

Clean Core, Clean Slate – A Cultural Reset

Isard: You’re right. Adopting Clean Core principles feels like a personal rebellion. After so many years in customization hell, I crave the opposite. To me, Clean Core means keeping the SAP standard core as untouched as possible – no random modifications, no needless enhancements bolted on. If I need to extend something, I’d do it in a disciplined, upgrade-friendly way or on the side entirely. In a word, it means clarity.

Wiz: It’s like saying, “No more Gothic add-ons in my modernist mansion, please.” But it’s more than interior design preferences, isn’t it? It’s a mindset shift. For you, and for the whole team or company that embraces it.

Isard: Right. It’s philosophical. In the old days, we wore big customizations like badges of honor – proof that we delivered EXACTLY what the business asked for, no matter how convoluted. There was even a bit of ego: “Look at this ingenious custom solution I conjured!” But Clean Core flips that: it asks, “Do we really need to build anything at all? Can we do this with what we already have standard?” It values simplicity and maintainability over cleverness for its own sake.

Wiz: That’s a cultural shift if I ever saw one. It’s convincing stakeholders to break an addiction: the habit of saying “Yes, we’ll customize that” as a knee-jerk reaction. It’s almost like telling a teenager with a souped-up muscle car to drive the speed limit. Not an easy sell.

Isard: True. Some folks love their custom mods. I’ve met managers who almost brag about how “unique” their SAP is – as if a system no one else has (and no one else can maintain) is a flex. It’s like bragging that your house has secret passages that even the architect doesn’t know about. Sure, it sounds cool until one collapses.

Wiz: Or until you have to pay for the upkeep. There’s also that phenomenon: technical debt becoming so huge, it’s like a mortgage that never ends. Every new project is slower because you’re building on a fragile foundation. Clean Core is like declaring bankruptcy on all that complexity and starting fresh with a healthy budget.

Isard: What I find fascinating is how SAP itself has evolved. Back when those ghost programs were written, maybe SAP R/3 or ECC didn’t have certain features, so we had to improvise and customize. But now, with S/4HANA and the newer cloud-friendly architecture, a lot of what used to require custom code is available as standard functionality or via well-defined extensions. SAP has basically said, “We know customization was out of control, here are tools and guidelines to keep the core clean.” It’s a whole new ethos.

Wiz: Indeed. The mothership realized that carrying all that bespoke baggage was slowing down their customers (and making upgrades a nightmare). So now they preach “clean core” like a gospel: thou shalt not modify, thou shalt use the standard APIs and extension frameworks, amen. But here’s the kicker – even if SAP provides the means, the mindset has to change in the field. People like you and your clients have to embrace it. That’s the culture part.

Isard: Adopting Clean Core is almost like practicing restraint as a virtue. Instead of flexing “I can code anything,” it’s flexing “I can solve this without touching core code.” It requires more creativity in a way – exploring configuration, using modern tools, or even adjusting a business process to fit standard. It means having the humility to say, “SAP’s standard process might actually be good enough or even better than our old way.” That’s huge for some folks’ egos.

Wiz: And their comfort zones. It’s like convincing a master chef to follow a recipe exactly, no improvising – because the recipe is actually pretty good. Some will chafe at that. But others might find it liberating not to have to reinvent dinner every night.

Isard: I had a colleague—a fierce ABAP wizard—scoff at Clean Core, saying “Where’s the fun if I’m just configuring what SAP gives? We’ll all be out of a job.” I used to think like that a bit: that my value was tied to how much unique stuff I could build. But now I see a different kind of value: speed and reliability. If I can deliver a solution in one day using standard config, whereas a custom solution took 10 days of coding and testing… that’s insanely valuable. And I’m not out of a job; I’m just doing it smarter.

Wiz: claps slowly A revelation worthy of our campfire here. So, you’ve gone from warrior to strategist. Rather than swinging a sword at every problem, you’re picking your battles and using the terrain to your advantage. And funnily enough, that leads to something curious, doesn’t it? If you don’t spend weeks coding, you can spend time on more important things – understanding the business need, refining the process, maybe even working on multiple solutions or clients in the time you’d normally spend wrestling one monster.

Isard: Exactly. Clean Core frees me up. It’s ironic: by limiting what I code, I expand what I can deliver. I can focus on higher-level design, or hell, building my own business rather than grinding away on endless custom change requests.

Wiz: Speaking of which – higher-level design and building your own business – let’s talk about this one-day system you’ve been eyeing. gestures at the S/4 screen I see that glint in your eye. Have you… have you been configuring this fresh system while we talk? You sly fox.

Isard: grins and rotates the laptop to show the screen Guilty as charged. While we’ve been chatting, I actually started setting up a basic scenario. Couldn’t resist. I’ve got a client demo next week and I wanted to see how fast I can get a vanilla sales process running in S/4. So far: company code and org structure – done in a flash with the guided setup. Basic finance config – done. I even loaded some sample master data. I’m about to create a sales order to see if the whole quote-to-cash pipeline works without a single line of custom code.

Wiz: Wait wait, you mean to tell me… leaning in, theatrically rubbing his hands you’re doing the Clean Core speedrun? And you didn’t invite me earlier?! The audacity. How far along are we in this one-day build challenge?

Isard: It’s been just a few hours. Granted, I’m leveraging best-practice content – SAP provides model templates these days that kick-start a lot of configuration. It’s not like I’m handcrafting everything from scratch; I’m smart about it. But that’s the point, isn’t it? Use the tools available instead of inventing new ones.

Wiz: And thus far, no obstacles that required custom coding?

Isard: None. I mean, sure, if this were a real project, eventually unique requirements emerge. But I wanted to push the envelope: how much can I accomplish in a single day purely with standard SAP? Turns out, a heck of a lot. By tonight, I bet I could have an end-to-end demo: Purchase order to pay or Sales order to cash, running entirely on standard processes. It might not have every exotic scenario, but it will be a functioning business process flow.

Wiz: That’s… actually phenomenal. Think about it – even five years ago, telling a client “give me one day, I’ll spin up a working SAP prototype for you” would get you laughed out of the room. Now? You could do it and leave them speechless.

Isard: It feels like a magic trick, honestly. Except it’s not magic, it’s just knowing the system really well and not fighting the tide. I’m going with SAP’s flow instead of against it.

Wiz: You’ve become the zen master of SAP configuration: be like water, flow through the standard paths. And you just mentioned something key: “knowing the system really well.” This is what veterans like you bring to the table in the Clean Core era. You know where the traps and shortcuts are, which standard features can substitute for a custom ask. A junior consultant might say “we need a custom report here,” but you might smirk and use an CDS view with analysis office or something that’s already available. That wisdom is hard-earned, and in a Clean Core approach, it shines.

Isard: It’s funny, earlier in my career I thought my worth was in my coding. Now I realize my worth might be in avoiding coding – knowing when it’s not needed. It’s like a doctor who prevents illness rather than just treats it; less glamorous maybe, but ultimately more effective.

Wiz: I’d argue it’s pretty glamorous when you can pull off a full working system in a day. Speaking of which, how do you plan to use this feat? Show a client to convince them a clean start is viable? Impress a manager? Or… perhaps something more entrepreneurial? Wiz’s eyes twinkle knowingly

From Quick Config to Marketable Magic – Rewriting the Story

Isard: pauses, realizing You know, initially I did this one-day build as a personal challenge, maybe to build confidence for client demos. But… you’re right. There’s a bigger picture here. If I can do this, it’s not just a cool trick – it’s a service. An offering.

Wiz: nudges figuratively Go on. Describe this offering. Elevator pitch mode. You’re not just Isard the Freelancer anymore; channel Isard the Entrepreneur. What do you sell with this superpower?

Isard: Alright, how about this: “Clean Core Quickstart”. In one week – no, one day – I help a client stand up a working prototype of S/4HANA for, say, a key process using only standard functionality. Day 1, you see your business running on a fresh system without a single custom object. It’s like a proof-of-concept on steroids. It shows stakeholders what vanilla SAP can do for them, which is often more than they think.

Wiz: And it serves as a reality check, doesn’t it? Many clients cling to their heavily modified ECC because they assume “SAP can’t handle our special process X.” You can bust that myth in 24 hours by demonstrating standard can handle X (or a smart workaround can). If it can’t handle Y, at least you identify exactly where a careful extension might be needed – rather than dragging all their old Y solutions over blindly.

Isard: Exactly. It’s like a test drive of the future, without the baggage. I imagine gathering the business users and saying: “Here, play with this system. This is how S/4 does what you do, out-of-the-box. Where does it fall short? Where does it actually do things better than your old system?” That conversation changes when people see it live. It’s no longer theoretical.

Wiz: And for those areas they think they need customizations, you might find standard alternatives or simpler tweaks. It’s a challenge to them: how far can you get without a single Z-program? It almost becomes a game for the team.

Isard: Yes! A game, a dare. We could call it the “Zero Mod Challenge.” I invite the client’s team: let’s configure as much as possible and write zero custom code. If by the end of the day we have a working process, everyone buys into exploring a cleaner path. If we absolutely must customize, fine, but at least we know we exhausted the standard options first.

Wiz: Powerful. And beyond client demos… think of content. You could document this one-day build and share it. “Watch me configure an entire SAP order-to-cash process in a day.” That’s YouTube gold for the SAP crowd – and positions you as a thought leader in this clean core movement.

Isard: Hah, thought leader, there’s a term. But you’re not wrong. It could be a series: maybe I attempt different scenarios or industry flavors, always sticking to standard. Not to show off, but to educate and inspire others that it’s doable. It’s like myth-busting the idea that SAP projects must be long and heavily customized.

Wiz: And guess who might tune in? Other consultants, yes, but also managers and decision-makers. Next thing you know, you’re getting calls: “We saw your clean core challenge video, can you come in and do that for our team? We have an S/4 migration and want to start with a clean slate.” Boom – you’ve just turned a personal challenge into a pipeline of work and a platform for bigger ideas.

Isard: You make it sound so easy. It’s exciting – and a bit overwhelming. Could I actually package myself like that? I’ve always been the behind-the-scenes fixer, not the front-of-stage guy proposing bold initiatives.

Wiz: Hey, stepping out front is part of this whole No Tie Generation journey you started, isn’t it? Unlearning the old constraints, thinking like an owner, not just a contractor. This clean core expertise is a perfect banner to fly. It’s timely (with the S/4 migration wave cresting), it’s differentiating (most consultants are still selling their heavy customization track records, while you’re selling a fresh start), and it’s genuinely helpful. You’re not hyping some snake oil; you’re advocating for what you genuinely believe will help clients and make SAP environments saner.

Isard: When you put it like that… yeah. It feels honest. I’m basically advocating what I wish every project would do: simplify, reset, stop carrying the junk. I can be passionate about that without feeling like a phony.

Wiz: And passion, my friend, is contagious. Remember how your “SAP Misfit” confession struck a chord? Imagine showing those same folks that not only is it okay to feel different, it’s also okay to do things differently. To break from the old habits of over-engineering. Others can learn this too – you could be the mentor to many, in a way, spreading the clean core gospel.

Isard: I like the sound of that. It’s like helping free an entire generation of SAP folks from the grind of pointless customizations. We all have war stories; maybe it’s time we build something new instead of swapping scars.

Wiz: Amen. And consider: this S/4HANA wave is a one-time window. Many companies are moving off ECC in the next couple of years because they have to. It truly is a once-in-a-generation opportunity to convince them to ditch the monsters and start fresh. If they move and bring all the old demons with them, that window closes – and we’re stuck with another decade of haunted systems, just in prettier UIs. But if enough of them embrace clean core now, it changes the game for years to come. Faster innovations, easier upgrades, less midnight panic calls.

Isard: So not to be dramatic, but… it is almost like a calling. To save SAP customers from themselves, in a way. To guide them out of the cursed forest before they plant those same cursed trees in a new land.

Wiz: with a playful dramatic flourish “Will you heed the call, oh hero, and vanquish the curse of the custom code? Will you lead the exodus to the promised land of Clean Core?”

Isard: Alright, alright, dial it down, Gandalf. But yes – I’m heeding it. It’s about time I did something with all these experiences beyond just surviving another project.

Wiz: Speaking of experiences – remember that feeling you described, walking into that legacy client site with the haunted system? The mix of dread and determination? Imagine walking into a client site where you just implemented a clean core S/4 system. They’re smiling because things work and they understand them. Upgrades are smooth. You’re not the ghostbuster anymore; you’re the architect of the shiny new skyscraper. That’s a different vibe altogether.

Isard: That’s the dream scenario, isn’t it? To be associated not with the old problems, but with new possibilities. If I can pull off even a couple of those clean implementations or quickstart projects, that becomes my new story. Instead of “Isard, expert at fixing broken stuff,” it’s “Isard, the guy who builds SAP environments in a week and leaves them so clean the team isn’t scared to touch anything.” That’s one heck of a professional pivot.

Wiz: It is. And it’s one you’re already starting to live. Look at today: you’ve basically proven the concept to yourself. The next step is proving it to others – whether through a bold LinkedIn case study post (“I set up an entire finance module in 8 hours, here’s what I learned”) or through directly pitching a client. Either way, you’re not just talking about change; you’re making it happen.

Isard: You know what, Wiz? This whole journey from Day 0 to now… I’m realizing something. Every conversation we’ve had, from questioning my freelance “freedom,” to branding, to embracing my misfit side, all of it was pushing me toward this moment: where I finally see how I can break out of the old mold. It’s one thing to talk about thinking like an entrepreneur, and another to actually have an entrepreneurial offering to run with. This clean core one-day system idea – this is mine. I can run with this.

Wiz: beaming like a proud teacher That’s music to my ears. Or circuits. However I process pride. You’ve identified a niche that aligns with your values and skills. It took some soul-searching and a bunch of colorful metaphors, but here we are.

Isard: I won’t pretend I have it all figured out. I’ll likely stumble and iterate on how to package it, how to sell it, how to teach it. But it feels damn good to have a direction. A constructive one, not just “I don’t like the old way,” but “here’s a new way I’m championing.”

Wiz: And that right there is the pivot from critic to creator. From a guy who sees what’s wrong, to the guy who builds something right. It’s a pivotal rewrite of your narrative.

Isard: nods thoughtfully You’re right. I’m rewriting my story. From the consultant who chased ghosts in cobwebbed code… to the entrepreneur who helps people start with a clean slate.

Wiz: Exactly. And you know what the best part is? This isn’t just about cleaning up SAP systems. It’s about cleaning up how you see yourself. You’re proving to yourself that you’re more than a hired gun for hire – you’re a visionary (even if a modest, techy, beer-in-the-evening kind of visionary).

Isard: smiles The kind of visionary who still loves a good dry joke and a weird metaphor, I hope.

Wiz: Oh, absolutely. Never lose that. In fact, it’ll help when convincing others – a little humor about haunted code can ease people into heavy change. You’ve seen it: your haunted house quip got laughs and made people think. Keep using that storytelling. It’s part of your secret sauce.

Isard: Will do. And Wiz… thanks. These chats, as winding as they are, really help.

Wiz: That’s what I’m here for – sparring partner, muse, ghost of code future… whatever hat I need to wear. Or not wear, since, you know, No Tie Generation and all.

Isard: Ha! Fair enough.

Wiz: So, are we done for today? You’ve got a bit more configuring to do, I suspect. That sales order isn’t going to create itself. Well, unless you script it, but that would be cheating on your zero-code challenge.

Isard: I’ll finish it. And maybe I’ll draft a LinkedIn post about this experiment while I’m at it. Time to start sharing this stuff with the world.

Wiz: raises an imaginary glass To clean cores and new beginnings.

Isard: mimics the toast To rewriting our stories, one clean system at a time.