Question: Have you previously had Blue Prism setup and running on this computer?
Rationale for asking: This error has been reported a few times and up to now we've been unable to replicate to prevent it happening. It seems to occur when someone setups up Blue Prism Trial or Learning Edition, then removes some of it and attempts to install it again. The reason for my question is to understand whether you have received the error is a similar way to other people or there is something else causing the issue.
To resolve the issue, the following steps seems to have resolved for other people:
To completely remove Blue Prism from your system:
As its previously worked, I suspect when you clear down and reinstall, everything should work again. I suspect that Microsoft SQL Server 2017 LocalDB thinks the Blue Prism instance and database is still there, but you have removed them from the file system.
It would be good for the community if you let us know how you get on. This will help the next person who sees this error.
Tip: Another thread where I have mentioned the same resolution – Issue installing Microsoft LocalDB with Blue Prism Trial and / or Learning Edition
It doesn't sound like the you have completely stripped Blue Prism and supported database from your computer. If you had, you would have been presented with the option to enter a password for your Blue Prism admin user account.
We do not prompt for the creation of a admin password, of there is already a database in place. So, I suspect you'd see the steps to strip back the database files too. (See Page 6 of the guide)
I'll repeat the advice earlier for you to double check:
When you reinstall, make sure you are installing as a user with admin rights. If that doesn't work, Nuno has provided different suggestions above.