Resolving WinCC OPC DCOM Error 'The System Cannot Find the File Specified' (CLSID {75D00BBB...})

In SIMATIC PCS 7 and WinCC, remote OPC DA client connections fail with DCOM error 'The system cannot find the file specified' (referencing CLSID {75D00BBB-DDA5-11D1-B944-9E614D000000}) when the WinCC OPC DA server executable (SopcDaSrv.exe) is missing, unregistered, or its Windows registry keys are corrupted. This CLSID identifies the core OPCServer.WinCC component. To resolve the error, engineers must verify file integrity in the WinCC bin folder, re-register SopcDaSrv.exe and opcenum.exe using administrative command prompts, and execute the Siemens Security Controller to restore COM class registrations.

Role of CLSID {75D00BBB-DDA5-11D1-B944-9E614D000000} in WinCC

In SIMATIC WinCC and PCS 7 Operator Stations, the COM Class Identifier:

{75D00BBB-DDA5-11D1-B944-9E614D000000}

is the globally unique identifier (GUID) representing the SIMATIC WinCC OPC Data Access Server (OPCServer.WinCC):

Binary Mapping: In the Windows Registry under HKEY_CLASSES_ROOT\CLSID\{75D00BBB-DDA5-11D1-B944-9E614D000000}\LocalServer32, this key points directly to the physical executable file:
C:\Program Files (x86)\Siemens\WinCC\bin\SopcDaSrv.exe
Execution Flow: When a remote OPC client queries OPCServer.WinCC, Windows DCOM evaluates this registry key and attempts to spawn SopcDaSrv.exe. If the registry key points to an invalid path or if the executable is missing, Windows returns ERROR_FILE_NOT_FOUND (0x80070002 / "The system cannot find the file specified").

Root Causes of 'The System Cannot Find the File Specified'

When an HMI or OS server logs this event in the Windows System Event Log:

Quarantined or Deleted Executable: Overzealous corporate anti-virus software may falsely identify SopcDaSrv.exe or its companion DLLs as suspicious, quarantining or deleting the binary from C:\Program Files (x86)\Siemens\WinCC\bin\.
Corrupted Registry Pointers After Upgrades: During Windows updates or partial PCS 7 software updates, the LocalServer32 registry string may become truncated, point to a non-existent drive letter, or lose 32-bit/64-bit redirection (SysWOW64).
Incomplete WinCC Installation: The station was restored using an OS Client image or an incomplete setup profile that omitted the WinCC OPC Server software options.
Unregistered OPC Core Components: The standardized OPC Foundation binaries (opcenum.exe, opcproxy.dll) were deregistered or missing.

Step-by-Step Binary Verification and Re-Registration Procedure

To restore the missing OPC server component:

Step 1: Verify Physical File Presence

Open Windows Explorer on the affected station.
Navigate to:
C:\Program Files (x86)\Siemens\WinCC\bin\
Check for the presence of:
* SopcDaSrv.exe
* SopcDaSrvPS.dll
* OPCCommon.dll
If SopcDaSrv.exe is missing:
* Check the local anti-virus quarantine log and whitelist the Siemens directory.
* Copy the verified SopcDaSrv.exe binary from an identical, healthy WinCC node running the exact same PCS 7 version and update level.

Step 2: Manually Re-Register the WinCC OPC Server

Open an administrative Command Prompt (Run as administrator).
Navigate to the WinCC binary directory:
cmd cd /d "C:\Program Files (x86)\Siemens\WinCCin"
Execute the self-registration command:
cmd SopcDaSrv.exe /RegServer
Register the proxy-stub dynamic link library:
cmd regsvr32 SopcDaSrvPS.dll
Confirm that Windows displays the success dialog ("DllRegisterServer in SopcDaSrvPS.dll succeeded").

Step 3: Re-Register OPCEnum

Navigate to the Windows System directory:
cmd cd /d "C:\Windows\SysWOW64"
Re-register the OPC enumerator service:
cmd opcenum.exe /RegServer

Restoring OPC Registry Keys and Permissions

Once files are re-registered, restore system security templates:

Inspect Registry Key:
* Open regedit.exe.
* Navigate to HKEY_CLASSES_ROOT\CLSID\{75D00BBB-DDA5-11D1-B944-9E614D000000}\LocalServer32.
* Verify that the (Default) value reads exactly:
C:\Program Files (x86)\Siemens\WinCC\bin\SopcDaSrv.exe
Execute Siemens Security Controller:
* Open the Start menu and launch Siemens Security Controller.
* Click Repeat Settings to re-apply DCOM activation permissions and firewall exceptions for SopcDaSrv.exe.
Restart the computer.

Verification

Confirm that the WinCC OPC DA server functions properly:

Local OPC Scout Test:
* On the repaired machine, launch OPC Scout V10.
* In the navigation tree, expand Local -> OPC.SimaticNET / OPCServer.WinCC.
* Confirm that OPCServer.WinCC connects without error.
* Add a test tag; verify that live values update with Good quality code.
Remote Client Connection Test:
* On the remote client machine, trigger the OPC connection.
* Verify that the client connects and reads tags without generating DCOM error 0x80070002.
Windows Event Log Check:
* Open Windows Event Viewer (System log).
* Confirm that no DCOM errors referencing {75D00BBB-DDA5-11D1-B944-9E614D000000} are logged.

Limitations and Operational Precautions

Version Matching Mandate: When copying missing binaries like SopcDaSrv.exe from another station, the source station must run the exact same PCS 7 version, Service Pack, and Update level. Mixing binary revisions can cause memory crashes in CCProjectMgr.exe.
Anti-Virus Whitelisting: Ensure Siemens directories (C:\Program Files (x86)\Siemens\, C:\Program Files\Siemens\) are permanently excluded from real-time anti-virus scanning in accordance with Siemens PCS 7 security guidelines.
Administrative Elevation: Running /RegServer commands requires an elevated administrative command prompt; running without administrator rights fails silently without creating registry entries.

Engineer FAQ

What does CLSID {75D00BBB-DDA5-11D1-B944-9E614D000000} represent?
It is the unique COM Class ID for the SIMATIC WinCC OPC Data Access Server (SopcDaSrv.exe).
Why does DCOM report 'The system cannot find the file specified'?
The Windows registry key for the CLSID points to a missing, deleted, or corrupted executable file (SopcDaSrv.exe), or the registry path itself is invalid.
Can I copy SopcDaSrv.exe from another computer to fix the issue?
Yes, provided the donor computer runs the exact same operating system, PCS 7 version, and WinCC update level.
How do I re-register the WinCC OPC Server executable?
Open an administrative command prompt, navigate to C:\Program Files (x86)\Siemens\WinCC\bin\, and run SopcDaSrv.exe /RegServer.
What is the function of SopcDaSrvPS.dll?
It is the proxy-stub dynamic link library that marshals DCOM interface calls between the client application and the WinCC OPC server.
Why did SopcDaSrv.exe disappear from my WinCC installation?
The most common cause is corporate anti-virus software quarantining or deleting the executable due to a false positive detection.
Does registering SopcDaSrv.exe require restarting WinCC Runtime?
Registration should be performed while WinCC Runtime is closed; a system restart is recommended after running the Security Controller.
Where in the Windows Registry is the WinCC OPC server path defined?
Under HKEY_CLASSES_ROOT\CLSID\{75D00BBB-DDA5-11D1-B944-9E614D000000}\LocalServer32.
Does this error affect OPC Unified Architecture (OPC UA)?
No, this specific CLSID and error apply exclusively to legacy COM/DCOM OPC Data Access (OPC DA).
What utility automatically repairs Siemens COM permissions?
The Siemens Security Controller utility re-aligns all COM and DCOM permissions across registered Siemens automation components.

Technical References

Siemens Industry Online Support (SIOS) Portal: How do you configure and repair the WinCC OPC DA Server? (Entry ID: 109768431).
SIMATIC WinCC V7.5 Information System - OPC Server Architecture.
Microsoft Technical Documentation: COM Class Registration and LocalServer32 Specification.

Related Tags

PCS 7, WinCC, OPC DA, DCOM, CLSID, SopcDaSrv, Troubleshooting, Windows Registry

Resolving WinCC OPC DCOM Error 'The System Cannot Find the File Specified' (CLSID {75D00BBB...})