Dear Maintainer,
Start up digikam. On left of the window click on 'Similarity'. Select which
albums to search. Click on 'Find duplicates'. Crashes with "Fatal error".
Retry. Start up. Back to 'Similarity'. Albums are still selected. Click on
'Update all fingerprints'. Crashes with fatal error.
Retry again. Go to Tools->Maintainence->Rebuild Fingerprints->Scan for changed (faster).
Fingerprints rebuilt. Go back to Similarity->Find duplicates. Now it works.
Attached output from Crashed Processes Viewer