I’ve had exactly the same issue, see my post, [How to get rid of "stopsign" marked entries? - #8 by ThSve]. After testing a lot of solutions, I solved it by removing the mediabay database for both Groove Agent and Groove Agent SE. They are located in folder C:\Users<your user>\AppData\Roaming\Steinberg\Groove Agent SE_64 and C:\Users<your user>\AppData\Roaming\Steinberg\Groove Agent_64.
I did like this:
Close GA and GASE.
Then renamed the file mediabay3.db by adding .bak after in each folder.
When GA and GASE are run, the db-files will be recreated.
After confirming that everything is ok, you can delete the old .bak files. If not OK, delete the newly created files and remove .bak from the files and you are back to where you were.
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