Performance Counter Troubleshooting (2.x) - microsoft/ApplicationInsights-Java GitHub Wiki

Performance Counters identify a process by "Instance Name." This will be the executable name without the extension, e.g. a process running java.exe will have an instance name java. If there are multiple instances of the same executable, an additional identifier is appended. By default this looks like java#1, java#2. For some reason, the instance name can change after the process starts with the default naming scheme.

To workaround this, add a DWORD registry value named ProcessNameFormat with the value 2 to the key HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\PerfProc\Performance. This changes the naming scheme from java#2 to java_123 where 123 is the current process id. It also makes the name constant for the life of the process.