Brownfield: Preparing System Conversion

Your prepare-phase SI checks all came back clean months ago. Can SUM still halt the actual conversion over simplification-item checks?

A system conversion is more than a technical procedure — what second dimension of work will bite you if you plan only the software install?

Which single tool actually installs the S/4HANA software during a conversion, and how does SAP keep that tool current?

Your source ERP still runs on AnyDB, not HANA. Which SUM component performs the database swap during conversion, and does it move the app server?

Why can't you convert just the production system, and what step is mandatory for a conversion that you might skip for an ordinary upgrade?

What is the very first conversion run in a project, and what does that sandbox run buy you before you touch the development system?

When in the run sequence do you first draft the cut-over plan, and where do you rehearse the production conversion itself?

How do the custom-code and configuration adaptations you make in DEV actually reach the production system during its conversion?

How do you decide which SAP Fiori apps to introduce, driven by what your users actually run today?

Manually spot-checking migrated data eats downtime — which SAP framework reduces that effort, and what does it cost to license?

In what forms can you consume the simplification list, and how do you drill into one specific item like the Business Partner Approach?

After conversion this field behaves exactly as before for the business, yet it's the textbook case where a field-length change still breaks custom code and cross-system integrations. Which field is it, and what changed about it?

The 2022 simplification list has ~675 items — but roughly how many does a real company actually have to adapt, and what narrows it down?

Maintenance Planner finds an unsupported add-on. What are your options, and how does an uncertified partner add-on differ in how it's flagged?

At how many points does the SI check actually execute during a conversion project, and where should the first run happen for the best results?

Your prepare-phase SI check passed, but the same check inside SUM's run reports different results. What setup detail explains the mismatch?

Which two SAP Notes must be installed before SI checks will run, and what does each contribute?

SAP refreshes the SI catalog and its Notes continuously. Should you always run the very latest version through a production conversion?

An SI check turns red on a company code and its controlling area. What mismatch triggers it, and can you defer the fix past the conversion?

An SI check flags an important S/4HANA change that you genuinely don't need to handle before cutover. Must that negative result still block the conversion?

In what order should you analyze and adapt custom developments for a conversion, and why does the sequence matter?

Experience shows 30–50% of custom programs go unused after a few years. Which tools let you find the dead code and actually remove it before a conversion?

ABAP code keeps running on SAP HANA after the database migration — so why does moving to HANA touch custom developments at all?

Which tool and check variants flag the mandatory HANA-database code conversions — as distinct from the S/4HANA-specific ATC check?

The central ATC system and the Custom Code Migration app both run the same S/4HANA readiness checks. What does the app add that plain central ATC doesn't?

How does the Custom Code Migration app get out-of-scope custom objects actually deleted during the conversion, rather than just listing them?

Your custom programs post goods movements with MB01/MB11. What does the ATC run tell you, and is adapting them optional?

How can you browse which SAP objects change for each simplification item without scheduling a full ATC scan?

You've analyzed custom code during the prepare phase. When can most of the actual code fixes be applied — and what does that mean for planning?

During the technical conversion, which transactions handle your modifications to SAP standard objects — and how are the fixes propagated onward?

What does 'code pushdown' mean for custom ABAP on HANA, and does the conversion do it for you?

Beyond the simplification list, which three tools identify the actual adaptation tasks for a system conversion?

When would you reach for SAP Readiness Check instead of running the individual prechecks yourself?

Red SI-check errors block the conversion — so are yellow warnings safe to skip?

A classic dual-stack (ABAP+Java) system can't be converted directly — what must happen first, and why isn't disabling Java enough?

Your source system is non-Unicode. Can you convert to S/4HANA and handle Unicode afterward, or must it come first?

When can you start running SI checks — do you have to wait for the technical conversion project to begin?

Classic credit management is a 'no longer available in this form' item — what does that actually mean for your config?

The simplification list and the SI checks both deal with simplification items — what's the difference in what they tell you?

Roughly how many simplification items were in the list for SAP S/4HANA 2022, and what does that number tell you?

What does the simplification list cover that a plain 'list of removed features' would not?

What does ATC custom-code analysis actually hand you for a conversion — and what does it NOT do?

Maintenance Planner vs SI checks/ATC — what does Maintenance Planner uniquely own in the prep phase?

What three core system prerequisites must a source system meet before a system conversion?

Why is S/4HANA custom-code analysis run on a separate current ATC system instead of on the source ERP system?

An item is categorized only as 'modified' (not removed). Why can it still break your custom code?

Maintenance Planner is a cloud app on the SAP Support Launchpad — what credential gotcha blocks first-time access?

Why must customer-vendor integration (CVI) to Business Partner be done as a prerequisite, not as post-conversion cleanup?

Into which three categories are simplification items divided — and which one is most often mistaken for 'safe'?

What is the maintenance plan from Maintenance Planner actually consumed by during the conversion?

Besides add-ons, what target-release compatibility does Maintenance Planner check that can block conversion?

What distinguishes a system conversion's outcome from a new implementation — what survives?

What does the SAP BTP custom-code analysis option remove from your landscape compared with a central ATC system?

Under S/4HANA's 'principle of one', what happens to SAP ERP credit management (SD-BF-CM)?

Which S/4HANA deployment can you NOT reach via brownfield system conversion?

Why is moving from SAP ERP to S/4HANA a 'system conversion' and not an 'upgrade'?

Custom programs run slowly after the HANA move. Which custom-code patterns does ATC flag as the root cause before you blame infrastructure?

Which ATC variant do you select to analyze custom code for S/4HANA readiness?

ATC flags hundreds of custom objects to adapt. How do you avoid spending effort on code nobody runs?

Beyond simplification items, what does the Readiness Check dashboard add about business functions and Fiori?

How can you cut credit-management conversion effort before the conversion window even opens?

Three deployment options exist for custom-code adaptation analysis — what decides between them?

What must you upload to the analysis system before custom-code checks will give valid results?

A stakeholder pictures the S/4HANA conversion as three separate back-to-back projects. What three operations does SUM actually fold into one integrated 'one-step' run?

The core conversion runs clean, yet the target landscape still won't stand up. Beyond the database and the ABAP stack, which two environment compatibility checks were most likely skipped during target-architecture planning?

It's easy to assume SI checks only flag which simplification items apply to your conversion. What second, more active job do they enforce — and what were they called before S/4HANA 1709?

After the development system is converted, why do teams impose a coordinated 'system freeze', and when should it be announced?

Which business-function condition is a hard stopper that Maintenance Planner surfaces — one that no amount of remediation during SUM will resolve?

SAP Readiness Check already runs add-on, business-function and SI checks. So can it replace Maintenance Planner, the SI checks in ERP, and the Custom Code Migration app?

SAP Readiness Check and SUM Prerequisite Check Extended overlap on the SI checks. Can you just pick one?

When can you NOT convert in a single step, and does the source database have to be SAP HANA already?

Can you convert onto any SAP S/4HANA release you like, or does SAP restrict the supported targets?

How can you surface every blocking conversion error weeks ahead, without committing to a real conversion run that forces you to fix each error on the spot?

You want to run Prerequisite Check Extended, but the HANA target DB isn't provisioned yet and Maintenance Planner won't issue a full stack XML because of an unsupported add-on. What are your options?

How early can you run SAP Readiness Check, and do a non-Unicode or unlicensed source system block it?

For SAP Readiness Check, where do you implement the check reports and where do you actually run them — dev or production?

For a conversion (not a fresh build), which tool sizes the HANA database — and what is Quick Sizer actually for here?

Maintenance Planner asks how to deploy the SAP Fiori frontend server — what are the choices and which does SAP recommend?

During the transition you run two development systems in parallel — one on ERP, one on S/4HANA. How do you keep changes from diverging?

In Maintenance Planner, why must you start from 'Plan for SAP S/4HANA' rather than 'Explore Systems' when planning a conversion?

Maintenance Planner is a cloud app — where does it get your live system landscape data from?

SAP Warehouse Management still runs after conversion — so why does it appear in the simplification list at all?

You want to land the converted system on a hyperscaler instead of your own data center. Which SUM options relocate the system, and what's the precondition?

Which Maintenance Planner step can you run before buying any S/4HANA license, and what SUM-critical artifact does full planning produce?

What are the three project phases of a system conversion, in order?