Resolving WinCC TIA Portal Compile Crash and Reopen Failure

WinCC Professional and WinCC Runtime Professional projects compiled inside the Totally Integrated Automation Portal (TIA Portal) can complete the compile progress bar to 100% and then terminate the TIA Portal host process with a Windows error dialog. After the forced restart, double-clicking the affected .ap20 (or .ap19, .ap18, .ap17, .ap16) project may fail with no visible error, an immediate close, or a hang. This reference collects every officially supported recovery path, diagnostic capture, and prevention measure for the failure mode, with version-specific guidance for TIA Portal V16 through V20.

1. Problem Details and Symptom Matrix

Engineers encounter the failure in three distinct shapes. Each one drives a different recovery decision.

2. Root Cause Analysis

Six failure classes produce this symptom chain. Identify which one applies before changing anything destructive.

2.1 Project Database Corruption

TIA Portal stores each project as a SQL Server Compact Edition (SSCE) database inside the .ap<xx> archive. Interrupted writes, antivirus quarantine, and forced shutdowns can corrupt the page header, after which any compiler pass that reads the affected table triggers an unrecoverable exception. The most common culprits are unsaved HMI screen changes flushed at the 99-100% compile mark and the asynchronous re-indexer that runs immediately after.

2.2 WinCC-Specific Compiler Add-on Failure

WinCC Professional uses a separate compiler pipeline that is loaded only when an HMI device with WinCC Runtime Professional is part of the project. Bug fixes in this pipeline are released as TIA Portal service packs rather than WinCC redistributables. A known failure mode occurs when the project contains orphaned tag references, screen references, or library references that the WinCC post-processor walks recursively.

2.3 Non-English Regional and Locale Settings

Numbers, dates, and decimal separators in the Windows regional format other than English (United States) can cause the SSCE reader to fail on certain tag value initializers. The Windows display language can remain English; only the regional format must be set to English (United States). This is documented in the Siemens Industry Online Support FAQ entries for TIA Portal installation prerequisites.

2.4 Insufficient Disk Space, Long Paths, or UNC Storage

Compile output goes to the project folder, then to %LOCALAPPDATA%\Siemens\Automation\<version>\Cache. If the project resides on a UNC path, on a network share with intermittent connectivity, or on a drive with less than 5 GB free, the post-compile commit step throws and crashes the host. TIA Portal V18 and later refuse projects on UNC paths; older versions allow it and fail later.

2.5 Antivirus and EDR Interception

Real-time file system protection, controlled folder access, and ransomware protection features in Microsoft Defender, CrowdStrike, SentinelOne, and Trend Micro can intercept S7WBX.dll, HMICADif.dll, or the SSCE engine at compile time. The 100% mark is the threshold where the IDE finally commits the temporary files; the AV scan races the commit and the host faults.

2.6 TIA Portal Installation Inconsistency

Partial TIA Portal updates, mixed TIA Portal versions from uninstalled bundles, or missing redistributables (SQL Server CE, .NET Framework 4.8) manifest as 100% compile crashes after a Windows update or after installing a second TIA Portal version. The Start menu will show the correct version, but a file under C:\Program Files\Siemens\Automation may belong to a different release.

3. Pre-Recovery: Capture the Diagnostic Bundle

Before any destructive action, collect the official Siemens diagnostic data. Siemens Support cannot act on a verbal description of a compiler crash; they require the log bundle.

1. Open Windows Explorer and navigate to %LOCALAPPDATA%\Siemens\Automation\Logfiles.
2. Copy the three most recent ApLog.txt, ApLog.xml, and Siemens.Automation.Portal.exe.log files.
3. Navigate to %LOCALAPPDATA%\Siemens\Automation\<version>\Diag and copy the entire Diag folder.
4. If Windows Error Reporting produced a dump, copy it from %LOCALAPPDATA%\Microsoft\Windows\WER\ReportArchive or %LOCALAPPDATA%\CrashDumps.
5. Open the affected project once more by launching TIA Portal first, then File > Open, then selecting the project file. Watch the ApLog.txt in a tailing editor (Notepad++ or Get-Content -Wait in PowerShell) to capture the live failure line.

Siemens support requests reference number 109768498 (TIA Portal diagnostic data collection) in most product-support tickets; the resulting ZIP is the deliverable expected by the support engineer.

4. Recovery Workflow: Step-by-Step

Execute the steps in order. Stop and re-collect diagnostics if the failure shape changes.

Step 1: Verify Locale and Regional Settings

1. Open Windows Settings > Time & Language > Language & Region.
2. Click Regional format and select English (United States).
3. Open Control Panel > Clock and Region > Region > Additional settings and confirm the decimal symbol is . and the list separator is ,.
4. Sign out and sign back in. Reboot if any HMI runtime service is currently running.

Step 2: Move the Project to a Local Path

1. Copy the entire .ap<xx> file to C:\TiaProjects\ (create if missing).
2. Verify at least 5 GB free on the destination drive.
3. Right-click the project folder > Properties > Security and confirm the current user has Full Control, including on subfolders and files.

Step 3: Add TIA Portal Folders to Antivirus Exclusions

1. Add the following to Microsoft Defender's Controlled Folder Access or to your EDR's allow-list:
   • C:\Program Files\Siemens\Automation
   • %LOCALAPPDATA%\Siemens
   • C:\TiaProjects\ (or your project root)
   • %TEMP%\Siemens
2. Reboot to ensure the AV driver reloads with the new exclusions.

Step 4: Clear the Project Cache

1. Close all TIA Portal instances.
2. Open the project folder and locate any subfolder named .Cache or files with the .tmp extension.
3. Delete the .Cache directory. The SSCE engine rebuilds it on the next open.
4. Open %LOCALAPPDATA%\Siemens\Automation\<version>\Cache and delete the contents (not the folder).

Step 5: Open and Rebuild the Project

1. Launch TIA Portal first (do not double-click the project).
2. Select Project > Open and browse to C:\TiaProjects\<yourproject>.ap<xx>.
3. Wait for the project tree to fully populate. A slow first open is normal after cache deletion.
4. From the project tree, right-click the WinCC RT Professional device and select Compile > Software (rebuild all). The rebuild-all path is the documented recovery for partial-state projects and triggers a clean regeneration of all HMI tags, screens, and VB scripts.
5. Save the project before any further compile cycle.

5. WinCC-Specific Compile Settings

The official WinCC V20 documentation for Compiling a project (RT Professional) describes the compile pipeline in detail. The key points relevant to the 100% crash are:

• Consistency checking runs at the start of compilation. Errors are listed in the Inspector window; click each entry to jump to the offending object. A failed consistency check is the most common non-crash reason for an apparent 100% failure.
• The compiler stores intermediate files in the project folder under \IM\<device>\. A failed intermediate write manifests as a 100% crash with no Inspector entry.
• Cross-references to PLC tags that no longer exist, or HMI tags whose data type changed during a recent PLC program edit, are validated only at the final commit. These are the leading cause of WinCC RT Professional compile-time crashes that other panel types (Comfort Panels, RT Advanced) do not exhibit.

6. Project Integrity Verification

After a successful rebuild, perform the following checks to confirm the project is sound.

1. Close the project cleanly (Project > Close) without a force-close.
2. Re-open the project from disk; opening should take the normal time, not 5x normal.
3. Run Project > Compile > Software (rebuild all) again. The second compile should complete in the same time as the first and produce zero warnings.
4. Open the Inspector window, switch to the Compile tab, and confirm zero entries. A single warning about library versioning is acceptable; an error is not.
5. Run Project > Consistency Check > Display Consistency Check Results. All HMI devices should report Consistent.

7. TIA Portal Installation Repair

If the rebuild step in Section 4 still crashes the IDE on a project that opens cleanly, the TIA Portal installation itself is suspect. The repair sequence is:

1. Close all TIA Portal instances and stop the Siemens S7DOS Help Server and Siemens PLCSIM services if active.
2. Open Windows Settings > Apps > Installed apps.
3. Locate the TIA Portal entry (for example, "SIMATIC TIA Portal V20" or "SIMATIC STEP 7 / WinCC V20").
4. Click Modify > Repair. Accept the default repair scope.
5. Reboot after the repair completes.
6. Open the project, perform another rebuild, and confirm.

If the repair option is not available, use the original TIA Portal installation media and run Setup.exe with the /repair switch from an elevated command prompt. If the project was installed via the SIMATIC Software Installer, re-run the installer and select Repair on the TIA Portal component.

8. Version-Specific Notes (V16-V20)

These issue IDs are illustrative of the kinds of fixed defects shipped in TIA Portal updates; verify the current status in the official Siemens Industry Online Support portal (entry ID 109768498 and related).

9. Prevention and Project Hygiene

• Save project archives weekly via Project > Archive. Archives are .zap<xx> files and are immune to most SSCE corruption modes.
• Exclude the project root from real-time AV scanning, not just the TIA Portal install directory.
• Run a UPS on the engineering workstation. Forced power loss during a 99-100% compile is the leading documented cause of SSCE corruption.
• Keep at least 10 GB free on the project drive at all times. The post-compile commit uses a journal file that grows with project size.
• Update TIA Portal to the latest available update within your major version. The WinCC Professional compiler receives significant fixes in each update.
• Use TIA Portal Multiuser for projects exceeding 5,000 HMI tags. The single-user SSCE database struggles with concurrent reads during a full rebuild.

10. Escalation to Siemens Support

When the steps above do not produce a clean compile, escalate. The Siemens support process is:

1. Open a support request at the Siemens Industry Online Support portal with category "TIA Portal / WinCC" and sub-category "Compile / Build errors".
2. Attach the diagnostic bundle from Section 3.
3. Provide the TIA Portal version with update level (Help > About shows both the major version and the installed update), the Windows build number, the regional format setting, and the project size in MB.
4. Reference the affected WinCC device type (for example, WinCC RT Professional V20, image 4096 tags, 128 screens).

Include the support case number in any future interaction; Siemens tracks defects across the entire TIA Portal install base, and a detailed ticket contributes to the next service pack.

11. Verification Checklist

Use this checklist after every recovery attempt to confirm the project is stable before resuming work.

• [ ] TIA Portal opens to the start page without warning dialogs.
• [ ] Affected project opens via Project > Open (not by double-click) and populates the tree within 60 seconds for projects under 200 MB.
• [ ] Compile > Software (rebuild all) completes without a crash on the WinCC device.
• [ ] Inspector window shows zero compile errors and zero compile warnings.
• [ ] Consistency check returns "Consistent" on all HMI devices.
• [ ] Project saves cleanly and re-opens with no warnings.
• [ ] A new project archive (.zap<xx>) is created and stored outside the project folder.

12. Frequently Asked Questions