I paused a download (Google Drive) that was approximately 80%, then when I tried to resume the download it had started from scratch but the .part file had the correct size corresponding to that 80%.

I backed up the .part file and the cfg files.
Try to start a new download and replace the .part file but it didn't work.
I also reinstalled jdownloader and copy the backed up files but this generated false files.

I'm surely doing something wrong, thank you very much for your help