C135 PCS 7 (PCS7)
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How to Troubleshoot and Resolve STEP 7 'Server Busy' Errors After Installing WinCC

How to Troubleshoot and Resolve STEP 7 'Server Busy' Errors After Installing WinCC

To resolve the modal dialog 'Server Busy: This action cannot be completed because the other program is busy' when launching STEP 7 or SIMATIC Manager following a WinCC installation, engineers must resolve software version incompatibilities, release orphaned COM/OLE RPC locks, and configure Windows security policies. This error occurs when STEP 7 (s7tgtopx.exe) invokes internal Component Object Model (COM) interfaces to connect with WinCC database engines (CCProjectMgr.exe, CCDataServer.exe), but the target COM server fails to respond within the Windows RPC timeout window. The resolution requires verifying exact software version compatibility via the Siemens Compatibility Tool, running the Siemens Security Controller to repair DCOM permissions, executing CCCleaner.exe to terminate orphaned processes, and excluding SIMATIC folders from aggressive antivirus inspection.

Table of Contents

The COM/OLE RPC Architecture Behind 'Server Busy' Dialogs

In the Siemens SIMATIC software suite, SIMATIC Manager (s7tgtopx.exe) acts as the parent container for multiple integrated engineering tools (HW Config, CFC/SFC, NetPro, and WinCC Explorer).

Communication between these distinct applications relies heavily on Microsoft Component Object Model (COM) and Object Linking and Embedding (OLE) remote procedure calls (RPC):
1. When SIMATIC Manager launches or opens an integrated project, it broadcasts COM initialization queries to registered automation servers (such as the WinCC Project Manager).
2. Windows sets a finite RPC timeout (typically 10 to 30 seconds) for the target COM server to respond.
3. If the target service is hanging, blocked by an unhandled exception, waiting for a locked database handle, or hindered by security policies, Windows displays the system-modal message:
'Server Busy: This action cannot be completed because the other program is busy. Choose "Switch To" to activate the busy program and correct the problem.'
4. Clicking 'Switch To' or 'Retry' simply loops the query without resolving the underlying RPC deadlock.

Software Version Incompatibilities: STEP 7 and Standalone WinCC

The most frequent root cause of 'Server Busy' errors is installing a standalone version of WinCC (e.g., WinCC V7.3) onto a system with an incompatible STEP 7 version (e.g., STEP 7 V5.5 without required Service Packs):

  • Shared System DLLs: WinCC and STEP 7 share critical system libraries (e.g., s7otbxdx.dll, CCConfigStudio.exe, Microsoft SQL Server Native Client).
  • Database Schema Conflicts: Installing an unvalidated WinCC version updates shared SQL Server instances and registry keys, breaking STEP 7's ability to communicate with project databases.
  • The Compatibility Tool: Engineers must always cross-reference the Siemens Compatibility Tool (Kompatool) (https://support.industry.siemens.com/kompatool) before installing or updating WinCC on an existing engineering station.

Step-by-Step Remediation: CCCleaner and Security Controller

Follow this structured sequence to eliminate COM deadlocks:

Step 1: Clean Up Orphaned WinCC Processes

  1. Close all open applications.
  2. Launch an administrative Command Prompt and run:
    cmd "C:\Program Files (x86)\Siemens\WinCCin\CCCleaner.exe"
  3. Open Windows Task Manager; verify that no lingering instances of CCProjectMgr.exe, s7tgtopx.exe, or CCClientRT.exe remain in memory.

Step 2: Repair DCOM and Firewall via Siemens Security Controller

  1. Navigate to: Start -> All Programs -> Siemens Automation -> Security Controller.
  2. Click Repeat Settings.
  3. The Security Controller systematically restores:
    * Mandatory DCOM launch and access permissions for SIMATIC HMI and SIMATIC NET user groups.
    * Registry permissions for COM automation interfaces.
    * Windows Defender Firewall inbound/outbound rules for RPC port 135 and dynamic ports.
  4. Restart the engineering workstation.

Resolving Antivirus, DCOM, and Local Security Policy Deadlocks

If the 'Server Busy' prompt reappears after restarting:

1. Configure Antivirus Exclusions

Third-party endpoint protection (antivirus) software often intercepts COM inter-process memory pipes:
* Exclude the entire Siemens installation directory (C:\Program Files (x86)\Siemens\, C:\Program Files\Common Files\Siemens\).
* Exclude WinCC project directories (*.mcp, *.mdf, *.ldf).
* Exclude processes s7tgtopx.exe, grafexe.exe, and CCProjectMgr.exe from real-time heuristic monitoring.

2. Verify Windows User Group Memberships

Open compmgmt.msc (Computer Management) -> Local Users and Groups:
* Verify that your logged-in Windows user is an explicit member of:
* Administrators
* SIMATIC HMI
* SIMATIC NET
* Ensure the user password is not expired and that 'Simple File Sharing' is disabled.

Component Compatibility and Diagnostic Troubleshooting Matrix

The following table outlines diagnostic symptoms, root causes, and verified fixes for STEP 7 'Server Busy' errors:

Observed SymptomUnderlying Root CauseDiagnostic File / ToolVerified Remediation'Server Busy' on launching STEP 7Incompatible WinCC / STEP 7 versionsSiemens KompatoolAlign software versions with released SP/Upd'Server Busy' when opening OSOrphaned CCProjectMgr.exe processTask Manager / CCCleanerRun CCCleaner.exe; restart MSSQL$WINCC'Switch To' button loops indefinitelyDCOM access rights deniedWindows Event Log (DCOM 10016)Run Siemens Security Controller 'Repeat'Error occurs only for non-admin userMissing SIMATIC HMI group rightsLocal Users & GroupsAdd Windows account to SIMATIC HMI groupFreezes during project saveAntivirus scanning locked .ldf fileWindows Resource MonitorAdd mandatory antivirus folder exclusions

Maintaining compatible software baselines guarantees stable, deadlock-free engineering environments.

Verification

To verify that the 'Server Busy' issue is completely eliminated:
1. Launch SIMATIC Manager as Administrator.
2. Confirm that the application opens directly into the project selection dialog within 5 seconds without triggering 'Server Busy' popups.
3. Open an integrated PCS 7 multiproject containing both AS charts and a WinCC OS.
4. Open the WinCC OS project from SIMATIC Manager; verify that WinCC Explorer launches smoothly and mounts the project database.
5. In Windows Event Viewer -> System and Application logs, confirm that zero DCOM Error 10016 entries are registered.

Limitations and Operational Precautions

  • Never install standalone commercial WinCC releases on a dedicated SIMATIC PCS 7 Engineering Station; PCS 7 requires specifically bundled and tested WinCC releases.
  • Do not disable the Windows RPC service or DCOM machine-wide, as this cripples all STEP 7 communications.
  • If a Windows operating system upgrade was performed in-place, clean uninstallation and reinstallation of the SIMATIC engineering suite is strongly advised.
  • Always validate final license quantities, module availability, and MLFBs against the applicable Siemens catalog and authorized distributor quotation.

Engineer FAQ

Why does clicking 'Switch To' in the Server Busy dialog never work?

'Switch To' attempts to bring the unresponsive application to the foreground. Because the COM server is typically a hidden background service (CCProjectMgr.exe) locked in an RPC wait-state, bringing it forward cannot clear the deadlock.

Can running STEP 7 as Administrator resolve Server Busy errors?

Yes, in many cases. Running SIMATIC Manager with elevated administrative privileges bypasses restrictive User Account Control (UAC) token filtering on local DCOM interfaces.

Where is the Siemens Compatibility Tool found?

The Siemens Compatibility Tool is accessible online at https://support.industry.siemens.com/kompatool and allows users to cross-check operating systems, STEP 7 versions, and WinCC releases.

Technical References

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Related Tags

  • Server Busy
  • STEP 7 WinCC Compatibility
  • DCOM Permissions
  • Security Controller
  • CCCleaner
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