BUG: Installing Later Version of Common Language Runtime Creates Duplicate Performance Counters on Windows Server

On Windows Server, if you install a version of the common language runtime that is newer than the one that is currently on the system, you will see two sets of available performance counters for ASP.NET that have the same names.

For example, if a system has an initial version of 1.0.3215.11 and you then install version 1.0.3423.0, the following is what you would expect to see in the list of available performance counters: This is what you actually see: Note that both names of all the performance counters reflect the same version. However, they are not truly the same performance counters. The existing performance counters were renamed to reflect the most recently installed version. The performance counters should not have been renamed.

NOTE: This problem is not limited to the specific performance counters that are in the example.

This problem is caused by a bug in Windows Server. (The bug is not in the common language runtime or in the common language runtime installation program.)

Microsoft has confirmed that this is a bug in the Microsoft products that are listed at the beginning of this article.