I recently came across this error while using Jetstress to test and validate the performance of their Exchange storage. I was running the tool on Windows Server 2008 R2 and I don’t recall ever seeing this before. After finding what is actually an easy fix, I thought I would  write up this post just in case this has anyone else baffled. The entire error was:

Ensure that you’re running the application as a member of built-in Administrators security group.

The MSExchange Database or MSExchange Database ==> Instrances performance counter category isn't registered.

The admin account I was using is a member of the domain admins security group so I assumed I had the correct permissions but went away and checked just to be sure. I also checked to make sure that the domain admins group was a member of the local built-in Administrators security group, which it was. After spending a few minutes thinking about it, I thought I would try running Jetstress “as an administrator” (right-click the shortcut and select “Run as administrator”

That solved the problem.

I have since checked the Jetstress installation in my Exchange 2010 Lab which also runs on Windows Server 2008 R2 and this step is not required there, it works fine by just clicking the Jetstress shortcut (no right-click required). Not really worth spending time investigating the cause as it may just be a once-off occurrence, but at least it is now documented.