I've been upgrading a couple courses from moodle 1.9 to 3.3 following a lot of middle steps. All the backups have been successful and I've restored them up to 3.3 as I wanted, the only problem that I'm facing is that when backing up one of those course on moodle 3.3, the file created seems "corrupted".
Whenever I try to restore a 3.3 course backup, this is the error that I get:
Also, during the restore procedure, I can clearly see that some of the information is indeed corrupted:
As you can see, there are like "empty" files with no title or anything.
I tried extracting the backup and I compared it with a 2.8 backup of the same course. The file "files.xml" seems to lack some information on the 3.3 backup as you can see the difference here:
If anybody has any idea of why is this happening, I'd appreciate it a lot. Thank you for your time.