Today I was working on some plugin work and was On-Premise system and when I try click on Register new assembly via Plugin Registration Tool, I was getting “Object reference not set to an instance of an object” error.
If it was my machine, I could have downloaded XRMToolBox or latest Plugin Registration tool but I was working on the server and don’t have any permissions to download the required. I was completely stuck with it and don’t even know what to do.
After quick search, came to know that clearing contents in Appdata would solve the issue.
Navigated to “C:\Users\\AppData\Roaming\Microsoft\PluginRegistration” and deleted all the contents and then Plugin Registration started working normally.
Hope this helps.