Maybe I wasn't clear

The problem I described is with calibre export/import functionality
- First, in calibre, I used "export/import all calibre data/export all your calibre data" to export the whole library (as a result I got a folder with 298 files in the format part-xxxx.calibre-data, no error messages there)
- Then I tried to import it in the new installation, two methods:
- in the calibre, "export/import all calibre data/import previously exported data", got stuck 2/3 way through, no changes in the progress window, no disk activity
- in the terminal with calibre-debug, all metadata was imported, but only 2/3 books, the latest entries are just empty directories, during the import the terminal listed all the titles imported, the last entry is the word "Killed"
my question is: what can I do to import library successfully, or, if this is not possible, how can I unpack the exported data (those part-xxxx.calibre-data files) to retrieve books manually?