I have copied the catalog and photos from the old computer, and was able to view, edit and export photos.
Now i wanted to import the new photos from a SD card reader. The contents of the card are seen in preview and i could choose what i want to import. When i pressed "import" button nothing happened for a long time ("Importing files..." message appeared)
When i canceled the operation and wanted to restart - the import button was grayed out and i could not start it up.
The disk is not protected - i can copy the files manually.