[MarDer]

Go to the Songs display
Tap the 3 vertical dots (top right)
Tap "Show Filters"
On the Genre (middle of 3rd line), press the down triangle
Set the Mode to UnAssigned (or alternatively Select All and set Mode to Exclude)
The resultant display should be solely those without a Genre

Long Press one of the songs until the tick shows
Select all songs by tapping the open square box (bottom right)
Delete Song (top line)

When doing major operations like this, it is always a good idea to make a backup before you start - this gives you something to recover to if you haven't quite got it right.
I do this with the Companion (it requires a window pc) because this means the backup is not on the same device as the MSP installation.

Geoff
Geoff,
Thanks I tried your suggestion but on deleting the 4551 songs MobileSheets crashed.  I'll keep trying.
Ian

Has there been a resolution to this? I'm trying to figure out how to delete all Composers no longer connected to any song.

Yes this worked for me, I suggest you use the same instruction substituting Composer for Genre
Ian

Thanks, Ian. So your crash proved unrelated to the procedure? In your example, you were deleting Songs that had or lacked a certain attribute. I only want to delete Composers values that have no Songs associated with them. I'm very cautious!

did you found a solution for this problem?