Resolving WinCC 7.4 SP1 Startup Failure on Windows 10

Resolving WinCC 7.4 SP1 Startup Failure on Windows 10

Affected products: SIMATIC WinCC V7.4 SP1 (engineering & runtime), WinCC flexible 2008 SP5, TIA Portal V13 SP1, TIA Portal V13 SP2, TIA Portal V14 SP1.
Operating system: Microsoft Windows 10 (1607 / 1703 / 1709 / 1809 / 1903 builds verified in the field).
Symptom: SIMATIC WinCC Explorer icon loads, the "WinCC Explorer / Control Center" window flashes once, then the application exits silently. No WinCC project loads, no error dialog is displayed, and the process disappears from Task Manager within 2-3 seconds.

1. Problem Description

A clean installation of SIMATIC WinCC V7.4 SP1 on a Windows 10 workstation appears to succeed - the installer completes, the SIMATIC WinCC program group appears in the Start menu, and double-clicking the WinCC Explorer shortcut launches CCExplorer.exe. The splash screen is painted for approximately one second. The window then closes without any user prompt, no project is loaded, and the process is gone from Task Manager. Launching with "Run as administrator" produces an identical result.

This fault occurs most frequently when the workstation is a multi-purpose engineering seat that also hosts:

• WinCC flexible 2008 SP5 (or earlier Hotfix chain)
• TIA Portal V13 SP1, V13 SP2 or V14 SP1 (any edition: Basic, Comfort, Advanced, Professional)
• STEP 7 V5.5 / V5.6
• Third-party MS SQL Server instances (full SQL Server or SQL Express)

The root cause is almost always one of three underlying issues:

1. Installation order violation. WinCC flexible 2008 SP5 was installed after WinCC 7.4 SP1, replacing the bundled SQL Server 2008 R2 instance with an incompatible instance.
2. Missing user-group membership. The engineer / operator account is not a member of the local Simatic HMI group, so CCExplorer cannot acquire the registry hive under HKLM\SOFTWARE\Siemens\Automation.
3. User Account Control (UAC) still active. UAC tokens strip write privileges on %ProgramData%\Siemens\Automation and HKEY_LOCAL_MACHINE\SOFTWARE\Siemens, even when running elevated through the manifest.

2. Compatibility Matrix

Before re-installing anything, validate the combinations on your target PC. The Windows 10 rules differ significantly from Windows 7 / Server 2008 R2.

3. SQL Server Compatibility Layer

SIMATIC WinCC V7.4 SP1 internally uses Microsoft SQL Server 2008 R2 SP3 (Express) as the project database. WinCC flexible 2008 SP5 uses the same SQL Server 2008 R2 bit version but a different instance name and collation. Installing WinCC flexible after WinCC V7.4 SP1 overwrites the SQL 2008 R2 binaries under %ProgramFiles%\Microsoft SQL Server\MSSQL10_50.WINCC, which leaves the WinCC V7.4 SP1 database engine pointing to a non-existent MFC application boundary, hence the silent exit.

Quick SQL Server verification on the troubled workstation:

1. Open an elevated cmd.exe.
2. Run: sc query MSSQL$WINCC — the service state must be RUNNING; start type must be AUTO_START (Delayed).
3. Run: sqlcmd -S .\WINCC -E -Q "SELECT @@VERSION" — the reply must contain 10.50.6000 or higher (SQL 2008 R2 SP3).
4. If the WINCC instance is missing entirely, WinCC 7.4 SP1 setup did not complete its database stage. See Section 7 for reinstall procedure.

4. Required User Account Configuration

WinCC 7.4 SP1 reads and writes Windows registry keys under HKLM, files under %ProgramFiles%\Siemens\Automation and %ProgramData%\Siemens\Automation, and DCOM launch permissions across the WCCOA / WinCC scope. A standard Users-group account cannot do all three on Windows 10 due to ACL tightening introduced in 1607.

4.1 Local Group Membership

Add the engineering / runtime operator account to both local groups:

PowerShell / net command to verify and add membership:

net localgroup "Simatic HMI"
net localgroup "Simatic HMI" %USERNAME% /add
net localgroup "Administrators" %USERNAME%

4.2 Verify the SID SeAssignPrimaryTokenPrivilege

WinCC's runtime service account requires SeAssignPrimaryTokenPrivilege and SeLockMemoryPrivilege. From an elevated cmd.exe:

If the privileges list is empty, the user is being filtered by UAC. Resolve this via section 5.

5. User Account Control (UAC) Configuration

The single most common cause of silent WinCC exit on Windows 10 is UAC. SIMATIC WinCC V7.4 SP1 was developed against the UAC contract valid for Windows 7 (default elevation behavior). On Windows 10 the default UAC level is the third slider position, which strips write access even from elevated tokens.

5.1 Required Value

Open the Local Security Policy editor or set the registry value:

1. Press Win+R, type secpol.msc, press Enter.
2. Navigate to Local Policies » Security Options.
3. Open "User Account Control: Behavior of the elevation prompt for administrators in Admin Approval Mode".
4. Set to "Elevate without prompting".
5. Restart the workstation.

Equivalent registry edit (HIGHLY recommended for repeat deployments):

reg add "HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System" \
  /v ConsentPromptBehaviorAdmin /t REG_DWORD /d 0 /f
reg add "HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System" \
  /v PromptOnSecureDesktop /t REG_DWORD /d 0 /f
reg add "HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System" \
  /v EnableLUA /t REG_DWORD /d 1 /f
shutdown /r /t 5

6. Verified Installation Sequence

The exact order documented in Siemens KB entry WinCC V7.4 SP1 installation requirements for mixed WinCC / TIA systems on Windows 10:

1. Install all Windows 10 updates and reboot. Confirm build via winver.
2. Disable anti-virus during the entire sequence. Windows Defender real-time protection must be turned off.
3. Set UAC as described in Section 5 and reboot.
4. Add the engineering account to Simatic HMI and Administrators groups. Log off and back on.
5. Install WinCC flexible 2008 SP5 first. Accept all defaults. Note the CC_FLEX_SP5 SQL instance.
6. Install STEP 7 V5.5 SP6 (or V5.6) if needed. Compatible.
7. Install WinCC V7.4 SP1 second. The setup will detect and use the SQL 2008 R2 binaries deployed by WinCC flexible.
8. Install TIA Portal V13 SP2 and/or TIA Portal V14 SP1 editions Basic, Comfort, or Advanced ONLY. Professional is forbidden on a WinCC 7.4 SP1 PC.
9. Reboot. Launch WinCC Explorer as the engineer user (no "Run as administrator" is needed at this point).
10. Re-enable anti-virus after WinCC has verified a project loads and the runtime starts.

6.1 Unattended Install Command

For larger deployments, WinCC V7.4 SP1 supports /silent install. From an elevated cmd.exe on the source media:

D:\WinCC_V74_SP1\Setup\Setup.exe /silent \
   /products="WinCC V7.4 SP1" \
   /sql="Microsoft SQL Server 2008 R2 SP3" \
   /norestart

The mandatory prerequisite chain (each is its own setup.exe invocation):

VC2013RUNTIME_x86.exe /quiet /norestart
DotNet48-KBxxxxxx.exe /quiet /norestart
SQLServer2008R2SP3-ENU.exe /qs /ACTION=install /FEATURES=SQLENGINE
WinCC_V74_SP1_Setup.exe /silent

7. Re-install Procedure (When Setup Itself Failed)

If you are sure the install order was wrong or UAC was on during first setup, perform a clean re-install. This is the canonical Siemens field procedure:

1. Open Control Panel » Programs and Features.
2. Uninstall in reverse dependency order:
   - TIA Portal V14 SP1 (if present)
   - TIA Portal V13 SP2 (if present)
   - SIMATIC WinCC V7.4 SP1
   - SIMATIC WinCC flexible 2008 SP5
   - STEP 7 V5.5 / V5.6
   - Microsoft SQL Server 2014 TIA instance (if applicable)
   - Microsoft SQL Server 2008 R2 instance last
3. Manually delete leftover directories if they exist:
   

   rd /s /q "C:\Program Files\Siemens\Automation"
   rd /s /q "C:\ProgramData\Siemens\Automation"
   rd /s /q "C:\Program Files (x86)\Siemens\Automation"

4. Clean registry leftovers (run as administrator):
   

   reg delete "HKLM\SOFTWARE\Siemens\Automation" /f
   reg delete "HKLM\SOFTWARE\Wow6432Node\Siemens" /f

5. Reboot. Confirm Programs and Features shows no Siemens / TIA entries.
6. Re-execute the install sequence in Section 6 with UAC disabled and user groups configured.

8. Verification Checklist

After the corrected install sequence, validate each item before declaring the workstation healthy:

9. Log & Diagnostic Locations

When WinCC Explorer still does not stay open, harvest these artefacts before calling support:

Enable verbose WinCC logging before you reproduce the failure:

set CCEC_TRACE=1
set CC_TRACE_LEVEL=3
"C:\Program Files\Siemens\Automation\WinCC\bin\CCExplorer.exe"

10. Troubleshooting Matrix

Map the failure signature to the most probable cause. Start at the top of the table and work down - higher rows fix the majority of cases.

11. Frequently Asked Questions