Since the earlier thread has been closed I am starting over again here. I was told that I needed 4.23 to resolve the pfc.sys issue I was having. I purchased another year of Microstudio bug fixes from MTU in order to get this current release.
My first install of 4.23 did not remove the pfc lower filter as expected, so I uninstalled Microstudio and rebooted. The pfc issue remained so I manually removed pfc from the lower filter keys in all three registry control sets. Additionally I removed any refrence to pfc.sys in the shared dlls and deleted the file itself. Upon reboot the error was gone so I reinstalled Microstudio 4.23. Low and behold all the pfc files and registry keys were reinstalled with Microstudio as well as the return of the errors.
I thought this was supposed to be fixed with 4.23