We were looking at a `clr.dll` exception in some old janky software running on Windows 7. We were attempting to start a Performance Monitor to keep track of the percent of time that the application was being garbage collected. When we went to Performance Monitor we weren't able to add the traces because the ".NET" sources were missing. The Performance Monitor application was also giving an error right away that the Processor and Memory counters were missing. (These are the default counters that are present when you open the application.) To resolve the issue the following commands were run: 1. Reload the counter configuration from a previous backup `lodctr /r` 2. Add the .NET sources back in `lodctr C:\Windows\Inf\.NETFramework\corperfmonsymbols.ini`