I’m perplexed.
I accidentally merged a third album with a Wagner opera set of two -> 3 albums. As the procedure to “unmerge” does not seem to work I decided to delete the newly merged set and then reinstall the flac files from another HDD “X”.
Using Windows Explorer the albums no longer appeared on the Roon HDD “R”.
But when I tried to copy from the FLAC files from X to R one message was that the files already existed. Another time it appeared to copy from X to R but then on opening up Roon an odd looking album appeared so was deleted again.
This run around was done several times and quite often the earlier 3 album merge reappeared but as well another hashed album was also there.
So although the files appeared to have been deleted from R, when reinstalled it seems Roon recognised them as having previously been merged so kindly did it again.
In the end I shut down the PC altogether and checked Windows Explorer. None of the troublesome albums appeared to be in R. Yet when I tried to copy and paste I was told the files were already there!!!
I did get the albums reinstalled in the end but it was quite a run around and waste of time. It appears that “deleting” does not immediately delete and it takes awhile for Roon to digest this process – correct?
Please can we have an easy way of unmerging albums accidentally put together. It looked as if that was possible using edit -> fix track grouping -> edit discs -> remove -> yes I’m sure but then nothing appears to happen with the “Create Album” tag not highlighted. Or am I missing something???
Actually, when an album is removed from a watched folder, Roon does not assume it is deleted, it assumes it is just offline. This way you can move files around in storage media without losing your edits.
In order to remove an album completely, you first remove it from watched media THEN you go to settings/library/clean up library. Clean up the files which will remove them from Roon’s database. And then move them back into a watched folder to be seen as a new album.
Thanks for this info. 
I need to remove a problem album from my music folder then re rip it back into the music folder. I didn’t know that simply removing the album from the watched music folder didn’t remove it from the Roon database.
Now I know how to get a “new” copy of the album in the watched music folder (hopefully this will fix an issue I’m having).
Not sure I still completely understand what is going on with deletions.
So, the delete from watched media simply hides the album and so it is still there, but cannot be detected by Windows explorer - is that correct? To completely remove it from the Roon database the file(s) must be cleaned up via the library.
But I’m unsure I understand what is meant by : And then move them back into a watched folder to be seen as a new album.". Do you mean they can then be reinstalled from an external database to start over again?
I just had a weird occurrence which probably relates to the above. I had collated 7 albums but they disappeared. So I re-booted Roon to see if they would emerge, but still no sign of them. Next move was to go to where the original FLAC files were located and re-copy them all in for that artist. Of course I was told there were duplications so I elected to replace all previous files. Went back to Roon and initially they were not there but a minute later they suddenly popped up, and with all previously allocated tags correctly attached.
That was a bit perplexing as previously all merged albums (even 17 or more) appeared without any problem so I cannot understand what was different/special about this collation of 7.
And am I correct in understanding that, at the moment, it is not possible to break up a mistaken merge? The procedure appears to be Edit -> Edit Track Grouping -: Edit Disks -> remove _. Yes I am sure -> … nothing happens. Or am I on a completely wrong path? This is the third time I’ve asked about this but have received no response yet, unless I’ve missed it.