Backup and restore

Have you tried backing up a section at a time? Just backup part of the course, then another part and maybe a third part - depending how big it is. Be selective, and make sure you identify exactly what you are backing up in each part.

The reason I suggest this is that backing up can take a lot of resources, and if the resources are not available, then is going to spit the dummy at some stage. Should be OK, though.

It is possible there is something acting like a furball in an assignment or some such, causing the backup to choke. What should happen is if you have a smaller backup , it should work so you do the next part. If size has been the problem, then it will complete the sectional backup successfully. If it spits in the first part, but not the second, or vice-versa, then try and narrow what you are backing up, until you get a clear backup, then you have a good chance at finding what it is choking on.

The alternative is something has gone wrong in your backup pages. To save some time, you might want to FTP a new set of pages for the backup folder. That is, from your Test site, using FTP, delete your backup folder then just replace it with your test site folder. Be much quicker than downloading and updating. Or do this first, try it again, then if it repeats the behaviour, then you have lost nothing - but you have eliminated corruption of the code.

Of course, this takes time, and there may be a quicker way of doing this. If you backup parts of the course, then restore it later, just make sure you set the restore to add to the existing course.