Fault Tolerant Heap (FTH)

The performance when starting the programs or working in the program has become noticeably worse. What could be the cause of this?


Performance problems may be caused by the Fault Tolerant Heap (FTH). This is a Windows subsystem that is responsible for monitoring application crashes to prevent future application crashes.

To check whether the application (RFEM, RSTAB, RSECTION, and so on) is in the list of the applications to be checked, it is worth taking a look at the Windows registry. You will find the list in the following key:

As an alternative, you can also view the entries in the Windows Event Viewer. You will find it in the following path:
Applications and Services Logs → Microsoft → Windows → Fault Tolerant Heap

To reset the list of affected applications, run the command prompt as an administrator and enter the following command:
Rundll32.exe fthsvc.dll,FthSysprepSpecialize


Running this command will delete all FTH applications, so applications that are currently working properly may crash again after running this command.

The list should then be cleared and the application can be restarted without restrictions. If the problem occurs frequently, you can disable the FTH completely. The procedure and a summary of the FAQ can be found on the Microsoft Website.


Mr. Rehm is responsible for developing products for timber structures, and he provides technical support for customers.