ERROR_SEM_IS_SET: What It Is and How to Fix it

ERROR_SEM_IS_SET, or system error code 102 (0x66), as Microsoft puts it, is accompanied by the message ‘The semaphore is set and cannot be closed.‘ Users have reported this frustrating issue after upgrading their Configuration Manager from 2010 to 2013.

When they tried to install a management point (MP) on a secondary site, the installation process failed, and the message “Child process exited with non-zero code 102” was showcased.

What is ERROR_SEM_IS_SET?

ERROR_SEM_IS_SET’s log file displays messages such as “The semaphore is set and cannot be closed. ” This is important because semaphores originate from computer science and refer to a protected variable or abstract data type used to control access to shared resources in a multiprogramming environment.

They were invested to prevent situations where multiple processes compete for shared resources, leading to unpredictable outcomes, such as lagging, security issues, or freezing.

What causes ERROR_SEM_IS_SET?

It was discovered that the issue causing ERROR_SEM_IS_SET was related to the performance counters of the server’s SMS notification server.

The rolesetup.exe process, a Configuration Manager component, invoked the unlodctr.exe command to unload performance counters for the SMS notification server. However, the process failed.

How to Fix it:

To resolve ERROR_SEM_IS_SET, administrators are advised to:

1. Open Command Prompt with admin rights.
2. Run the following command: cd \\windows\\system32
3. Wait for it to succeed, and then run the command: lodctr /R

If these steps don’t work, you can also try to:

1. Uninstall the Management Point role from the Configuration Manager console.
2. Delete the CCM name instance from Windows Management Instrumentation (WMI).
   • You’ll need to open WBEMTest.
   • Connect to root.
   • Select enum classes.
   • Choose Recursive, and then OK.
   • Go to Query Results.
   • Look for _NAMESPACE, then double-click it.
   • Select Instances.
   • Highlight _NAMESPACE.name=”ccm” value and delete it.
3. Then, after you successfully delete the CCM name instance, install the MP again.

It’s worth noting that the Windows Management Instrumentation (WMI) in Windows 11 was deprecated earlier this year, so newer devices might not be affected by the ERROR_SEM_IS_SET, at all.

Either way, by following these steps, admins can work around the semaphore error issue and install the MP role, successfully fixing the issue.

Have you encountered the semaphore error in the past, and if so, how did you resolve it? Let us know your solution in the comments section below.