A zolca file is a plain zip file. To check if it is corrupted you can try to open it as a zip file (e.g. using 7zip). You can also manually extract the zolca archive in the `~/openLCA-1.4-data/databases/<database name>` folder and add the corresponding entry in the  `~/openLCA-1.4-data/databases.json` file (just check how it is done for the other databases in that folder; but it is good idea to backup these files first; also, do this when openLCA is closed).