I have a couple 'large' extensions for ArcGIS that have been in development for a couple of years now. Recently I've found that the "OnStartup()" method in the Extension class is no longer getting hit when ArcGIS is launched. I have a feeling that something has gone with my COM registration.
Note that this is an extension, not an add-in.
The major issue I have run into is my default workspace for storing temporary files is being setup from this "OnStartup()" method (checks to see if the workspace already exists and has files in it, if not it will create the workspace at a default path). So, when I attempt to run a tool from the extension it crashes as it cannot find the path it expects to store temporary files. Interestingly, if I open the Customize->Extension menu in ArcGIS and un-check/check the extension the "OnStartup()" method runs. So, it's almost as if ArcGIS is treating the extension as if it were "off", even though it is checked in the extension menu.
I've gone way back and compared the extension class in source control and cannot find any changes that could have caused this error. This problem may have occurred when I installed the latest service pack, but I can't be sure.
Has anyone else encountered this? Any help would be greatly appreciated!