The setup

We use the build in Performance Monitor on our Windows Servers to chart the data. That way we can see in how much load running the web application Camping.Info results. We usually monitor “% Processor Time”, “Commited Bytes”, “Requests/Sec”, “Requests Current” and “Request Execution Time”.

The loss

The latter three did not show up after I repaired the mirror on the server. I could not add them back via Properties –> Data –> Add. The whole category ASP.NET v4.0.30319 was missing.

The solution

After trying a few things and googling, I finally found the answer on serverfault: http://serverfault.com/questions/25842/performance-monitor-cant-add-counters-from-net-data-providers (second answer).

All I had to do was to delete  the entry “Disable Performance Counters" in HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\ASP.NET_4.0.30319\Performance. Then I restarted the Performance Monitor and everything was fine. A was able to see the missing category again.