WinCC Flexible 2008 Startup Failure: system.messaging.dll Fix

Problem Overview

Siemens WinCC Flexible 2008 (SP2 / SP3 / SP4 / SP5) fails to complete startup. The splash screen appears and the progress indicator freezes while the runtime attempts to load:

C:\Windows\assembly\GAC_MSIL\System.Messaging\2.0.0.0__b03f5f7f11d50a3a\System.Messaging.dll

The file physically exists in the Global Assembly Cache (GAC), but the WinCC flexible 2008 loader (the Configuration and Runtime components both call into the same CLR host) never advances past the assembly bind. In virtually every documented case the root cause is a corrupted or incompatible instance of Microsoft SQL Server 2005 Express Edition, which WinCC Flexible 2008 ships with and depends on for its project archive, alarm logging, recipe database, and user administration stores.

The condition is reproducible after:

• An improper shutdown of the configuration tool (kill of HMIRTm.exe or CCLoadServer.exe during a write).
• Manual uninstallation of SQL Server 2005 components without running the WinCC Flexible maintenance routine first.
• Applying Windows security updates that replace mscorwks.dll / clr.dll in a way the embedded SQL broker does not accept.
• Re-imaging or restoring a system image whose SQLEXPRESS instance master database is stale.
• Side-by-side installation of a newer SQL Express (2008 / 2012 / 2014) that hijacks the SQLEXPRESS named instance expected by WinCC Flexible 2008.

Root Cause: Why System.Messaging.dll Hangs

The .NET Framework 2.0 GAC bind for System.Messaging (strong name 2.0.0.0__b03f5f7f11d50a3a) succeeds — that is why no Fusion Log error appears — but the managed caller inside WinCC Flexible's archive engine spins on a SqlConnection.Open() call routed through System.Messaging message-queueing code paths. When the local SQL instance SQLEXPRESS is broken:

1. WinCC Flexible attempts to open the database WinCCFlexible on (local)\SQLEXPRESS.
2. The TDS handshake fails (master database corrupt, login broken, or service not running).
3. The internal .NET managed deadlock detector waits up to 90 s before yielding the loader thread.
4. The splash screen remains frozen because the main UI thread is waiting on the same threadpool token.

This explains why reinstalling WinCC Flexible alone without removing the broken SQL instance does not fix the issue — the installer reuses the existing instance.

Affected Versions and Editions

Prerequisites for Recovery

Before executing the fix, gather the following:

• Original WinCC Flexible 2008 installation media or a verified DVD image (the install set must include the bundled SQL Server 2005 Express).
• Local administrator credentials for the engineering station.
• Project backups (.hmi, .fwd, .ldf archive of C:\Program Files\Siemens\Automation\WinCC Flexible\).
• License keys / license diskettes (these are tied to the host SID and may need reactivation after SQL reinstall on a domain controller).
• If multiple HMI runtime projects share the same SQL Express instance, schedule a maintenance window for all connected panels.

Step-by-Step Recovery Procedure

Step 1 — Stop All WinCC Flexible Processes

1. Open Task Manager → Details.
2. End the following processes if present:
   CCLoadServer.exe
HMIRTm.exe
HmiEs.exe
ProAgent.exe
WinCC flexible 2008.exe
3. Set the SQL service to disabled:
   sc config MSSQL$SQLEXPRESS start= disabled
sc stop MSSQL$SQLEXPRESS

Step 2 — Uninstall Microsoft SQL Server 2005 Express

Use Add or Remove Programs (XP) / Programs and Features (Win7/Server 2008 R2) and remove in this strict order:

1. Microsoft SQL Server 2005
2. Microsoft SQL Server 2005 Tools
3. Microsoft SQL Server 2005 Backward compatibility
4. Microsoft SQL Server Native Client
5. Microsoft SQL Server Setup Support Files
6. Microsoft SQL Server VSS Writer

If the uninstaller returns error 0x84BB0001 or hangs, run the cleanup tool:

setup.exe /ACTION=uninstall /FEATURES=SQL /INSTANCENAME=SQLEXPRESS /QUIET

Step 3 — Remove Orphan SQL Registries and Data Directories

After uninstall, delete the following if they still exist:

• C:\Program Files\Microsoft SQL Server\MSSQL.1\MSSQL\
• C:\Program Files (x86)\Microsoft SQL Server\ (on x64 hosts)
• HKLM\Software\Microsoft\Microsoft SQL Server
• HKLM\Software\Microsoft\MSSQLServer
• HKLM\Software\Wow6432Node\Microsoft\Microsoft SQL Server (x64)
• HKLM\SYSTEM\CurrentControlSet\Services\MSSQL$SQLEXPRESS
• HKLM\SYSTEM\CurrentControlSet\Services\SQLAgent$SQLEXPRESS
• HKCR\CLSID\{...}\Microsoft SQL Server Data Link orphans

Reboot the engineering station before continuing.

Step 4 — Uninstall WinCC Flexible 2008

From Programs and Features, select SIMATIC WinCC flexible 2008 and choose Uninstall. Accept the removal of the SQL dependency check. If the installer warns about residual data directories, allow it to clean them.

Step 5 — Reinstall WinCC Flexible 2008

1. Insert the original WinCC Flexible 2008 DVD (or mount the ISO).
2. Launch Setup.exe as administrator.
3. Choose Install → WinCC flexible 2008.
4. The installer detects that SQL Server 2005 Express is missing and prompts for setup. Confirm.
5. Choose the default instance name SQLEXPRESS. Do not rename it — WinCC Flexible hard-codes (local)\SQLEXPRESS in the registry keys HKLM\Software\Siemens\Automation\WinCC flexible\2008\Database.
6. When asked for authentication mode, select Windows Authentication (the default). Mixed mode is supported but rarely needed.
7. Complete the installation.

Step 6 — Activate License and Restore Project

1. Start Automation License Manager → transfer the license to the local license container.
2. Launch WinCC flexible 2008. The splash screen should now pass System.Messaging.dll in < 2 seconds.
3. Open File → Restore and select the latest .hmi backup. Alternatively, recompile from the original TIA / Flex source.

Verification

After the recovery, perform the following checks before returning the station to production:

Alternative Recovery Paths

In-Place Repair Without Full Uninstall

If a full uninstall is unacceptable (e.g., license activation server is offline), attempt a repair first:

1. Reinsert the WinCC Flexible 2008 DVD.
2. Run Setup.exe /repair and select Repair.
3. If the SQL Express instance is still unhealthy, the repair will fail at the database integrity step. Proceed to the full uninstall described above.

Repair Just the SQL Instance

1. Stop MSSQL$SQLEXPRESS.
2. From the SQL 2005 Express install media, run setup.exe with:
   start /wait setup.exe /qb REINSTALL=SQL_Engine REINSTALLMODE=OMUS
3. Reboot. Verify with sqlcmd -S (local)\SQLEXPRESS -E -Q "SELECT @@VERSION". Expected: Microsoft SQL Server 2005 - 9.00.5000.00 (Intel X86) or higher SP.

Rebuild the Master Database

Only if setup.exe /repair fails with error 29506 or 29528:

1. setup.exe /ACTION=rebuilddatabase /INSTANCENAME=SQLEXPRESS /SQLSYSADMINACCOUNTS=BUILTIN\Administrators /QUIET
2. Restore master, msdb, and WinCCFlexible from the last known-good backup.

Reference: WinCC Flexible 2008 SQL Dependency Map

Troubleshooting Matrix

Side-by-Side SQL Interference

WinCC Flexible 2008 is hard-bound to a SQL 2005 Express instance named SQLEXPRESS. Installing any of the following after WinCC Flexible can corrupt the binding and reproduce the System.Messaging.dll hang on next start:

• SQL Server 2008 / 2012 / 2014 Express with default instance SQLEXPRESS (collision).
• Visual Studio 2010+ with LocalDB (replaces SQLEXPRESS token).
• Microsoft Office Access with SQL Native Client 11.
• Antivirus quarantine of sqlservr.exe after signature update.

To detect collisions, run:

reg query "HKLM\Software\Microsoft\Microsoft SQL Server\Instance Names\SQL"

If more than one instance named SQLEXPRESS is present, stop and uninstall the foreign one, then perform the WinCC Flexible recovery procedure.

Preventive Maintenance Checklist

1. Schedule a weekly DBCC CHECKDB ('WinCCFlexible') through SQLCMD.
2. Exclude C:\Program Files\Microsoft SQL Server\ from real-time AV scans (add to exclusion list with a documented process; document the deviation in the cybersecurity plan).
3. Disable Windows Search Indexer on the SQL data and log folders.
4. Image the engineering station every quarter; verify the image includes a healthy SQLEXPRESS master database.
5. Never kill WinCC Flexible processes via Task Manager — always close from the File menu or send WM_CLOSE to WinCC flexible 2008.exe.
6. Apply WinCC Flexible updates only after confirming compatibility on a non-production engineering station.

Migration to TIA Portal WinCC (Long-Term Path)

WinCC Flexible 2008 reached end of life on 30 September 2020. New installations should consider migrating to TIA Portal WinCC (Comfort / Advanced / Professional panels). Migration utility: WinCC flexible → TIA Portal migration tool. Note that project variables, screens, and alarms migrate automatically; recipes and VB scripts require manual review.

FAQ