I have created a new version of a custom addin for SolidWorks. The addin adds a tab to the CommandManager which contains a bunch of buttons to macros. I have previously updated it without issue. However this time round I cannot make the Addin active in SolidWorks. When I go into the Addins list and tick the option to make the Addin active, close the Addins list and then reopen it the Addin is not ticked as an active Addins. I can tick and retain the Active at Startup option. The Addin appears in the Tools dropdown menu and I can expand it to show the list of macros, but they are all greyed out.

The last version of the addin I uninstalled before installing the new version. I have uninstalled the new version and reinstalled the old version and get the same behaviour. With the old version installed the greyed out list of macros shows the new list of macros from the new version. The Addin was not written from scratch but developed from a freely available source. I have checked the registry, keys appear correct.