I tried to do what you said to Benji but I dont have MyCoollection.cool
It says: C:\Users\'Name'\Documents\Coollector\MyCoollection and it is a coollection file
Simply, your Windows is configured to hide the file extension...
It only shows "MyCoollection", but it really is "MyCoollection.cool".
I found the backup files and when I clicked on the latest one I open with.... coollector and I have put more movies on the list and when I shut down and re-open on the shortcut they ar gone again.
When you've clicked your backup file, Coollector has used this file, instead of the default file.
If you click your backup file again, you'll find all your movies, but you won't if you open Coollector directly (because the default file is empty).
What you need to do, is replace the default file with your backup.
Go to your backup file and copy it (control + C).
Then move up to the parent directory (where your default file is), and paste your backup file (control + V).
=> the backup file will replace the default file...
Now you can launch Coollector, and have all your movies.