Tapisrv.exe Thread Uses Excessive CPU Time

A thread in Tapisrv.exe begins using an excessive amount of processor time (as much as 95% to 100%) when you run a TAPI server application under a heavy load of phone calls.

This problem occurs when the thread that is using all the processor time has become stuck in an infinite loop due to a problem in the ring management code.

To resolve this problem, obtain the latest service pack for Windows NT 4.0 or Windows NT Server 4.0, Terminal Server Edition. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:


NOTE: This hotfix requires TAPI 2.1. Applying this hotfix with a previous version of TAPI may cause unpredictable behavior.

Microsoft has confirmed that this is a problem in Windows NT 4.0 and Windows NT Server 4.0, Terminal Server Edition. This problem was first corrected in Windows NT 4.0 Service Pack 4.0 and Windows NT Server 4.0, Terminal Server Edition Service Pack 4.