Betreff: Katalog kann nicht importiert werden, da unbekannter Feher aufgetreten ist.

Hi @mksap2000, Thank you for reaching out! Sorry to hear about your trouble. Since this thread is a bit old, starting a new one with all the details of your issue might be best. That way, your comments won't get lost, and you'll get the help you need more quickly. I'll do this for you!

Could you please share more information, like a detailed description of your problem, the version of LrC you're importing the catalog into, and the version of the OS? Is the Hard drive you're importing the catalog into internal or external? 

In the meantime, you can check the integrity of the catalog by: Holding down the Alt (Windows) or Option (macOS) key while launching Lightroom> In the "Select Catalog" dialog box, browse to the catalog you want to import, select it, and check the box for "Test integrity of this catalog."

One workaround is to export the problematic catalog as a new, clean catalog and then import that new one.

• Open the catalog you want to import into Lightroom.
• Go to File > Export as Catalog.
• Choose a location to save the new catalog.
• Once the export is complete, open your main Lightroom catalog.
• Go to File > Import from Another Catalog and select the newly exported catalog.

Let us know how it goes! Cheers!