Continuing the discussion from PRIME 4 Restore DB:
Good day to you, dear @Anthony_DDJ,
thanks for the response and your offer, to contact me directly. I found a workaraound for the issue, but let me report on you:
In general I’m missing a workflow description in the manual or on your home page for backup and restore the track files. Phps. inMusic can please be so kind as to write down / create a flow chart for the procedures.
Imo the reason for my specific problem in restoring the playlist was that the USB stick is formatted in exFAT correctly, the hard disk on my server (where the backup files are stored) is formatted in NTFS, so only some basics are saved and the backup is not completely, respectively Engine DJ is not able to read the backup file properly by any reason.
I issued the backup file by a simple copy from USB stick (source) to server (target).
In the meantime I restored as follows:
I copied from the backup file the files from …\Engine Library\Database2\ *. * to the matching USB\Engine Library\Database2\ *.**.
And luckily, Engine DJ recovered the old playlist, hot cues, and loops on the USB, but this is not the actual status and the list is incomplete.
As I made a download file via export as *.csv before the playlist passed away, so I was able to amend the recovered playlist by hand. 
Your comment is highly appreciated to avoid such struggle in future.
btw.: Is there a way to set the fields in the export *.csv file? My idea is to download all fields from the meta file completely and the user should delete the fields, he doesn’t need.
Thank you very much for your assistance in this matter in advance.
Have a nice day and brgds from HAM
BeatMaster