Could be the digikam settings specific to that user...check
not sure which file is relevant, I just did a
to find them...
...well, the first appears to be a directory, and it's empty on my install. The other appears to be the configuration file...I would suggest renaming (or moving) it, instead of deleting it, just in case.
There should be a database with digikam as well (which stores all your image's locations) (digimak4.db
, I think). Getting that to recreate may help, also (but, digikam will have to rescan your library, again).