You need to uninstall the previous Plugin. In your AC application folder double click "Uninstall.RIO" which will remove the previous version and then you can install the new one.
GS has "screwed" this one up. You are not updating and the instructions are not clear. Also if you have 2 versions of AC installed (US and INT like I have) then you need to uninstall it on both.
eduardo rolón AIA NCARB
Another of the forum moderators.
Macbook Pro M1 Max 64GB ram
OS X 10.XX latest
AC26 US/INT -> AC08
Puerto Rico, BVI, Miami