Hi Andrew,
Well ... I went through all the styles methodically removing them by year until I was left with only the ZZ styles and STILL the error appeared.
In desperation I tried the same with Realtracks.
By the time this process was complete I was sick of seeing the error message and decidided on the nuclear option.

I renamed the bb folder as bbOld and did a full install of 2025 from Install Manager.


Everything is working now as exepected..

I then added in all me additional user stypes and songs. Tested again and all OK.

So, the problem was clearly inside that old BB folder, but where? I don't care now.

One thing that did puzzle me though, When I was initially trying to isolate the issue, I tried the 32 bit verion. This version complained about activation and that I didn't have a valid ticket! Anywqay, it still let me open the application and the styles rebuild was sucessful, with no error problem. This was going to be my workaround.

Why was I not able activate the 32 bit version and why did it not see the error that the 64-bit version did.