First I upgraded from NPM9.5 SP2 to SP4 - everything worked great after this upgrade.
Then upgraded from APM2.5 to 3 and the NPM module service keeps crashing and restarting (Windows event log is full of errors).
Unhandled Exception caught in APM Service Engine startup. The type initializer for 'SolarWinds.APM.Common.Licensing' threw an exception.
APM will not run.
I then did a repair on APM3.0 - still not running
I then re-applied 9.5 SP4 - still not running
One issue I run into every time I upgrade and run the config wizard is it tries to use local authentication to upgrade the DB. I am using Windows integrated authentication, so it fails with a totally unrelated message - something about a default DB not being assigned to the user.
I have to go into the registry and delete the installed modules entries every time before I run the CW.
Lesson learned - never upgrade on a Friday night.
I will be opening a support ticket on Monday morning.....