At the moment we have no automated enrollment running. We do use our own plug-in but it has been off for a few weeks now. So manual is the only method at the moment. I can see in the course accees logs that students were in the course until 12:51 AM. But today the roster is empty.
I have nightly backups of the database and a full copy of the site from a few weeks ago. This course shows all the students in the backup (of course). When I check for the records in mdl_user_students with the ids for the enrollment entries I can see in the backup, they're of course not there.
This might be happening more than we know as the auto-enrollment would have corrected these drops in the past. Auto-enrollment will be back on soon. But I'm more worried about why some classes are being emptied for no apparent reason.
moodle 1.5.3 (2005060230) on SuSE linux, mysql 4.0.18
Just a shot in the dark here, but each course has an enrollment duration setting that is normally set by default to unlimited, but it can be changed in the the settings area of course administration. Are you sure this isn't set to some specific number of days in some of your courses?
There is also a longtimenosee setting in the site Administration/configuration/variables area, but it sounds like this probably isn't your problem if it is only happening in specific courses.
The mystery continues,
The entire school in all courses un-enrolled all students from all courses and now will not allow manual or key enrollment in the courses locking all students out from everything.
If anyone has any insight to this I would appreciate it. I'm kind of freaking out right now.
moodle 1.5.2 is what we have running...
(this is the same as what I emailed you)
Have you checked your mdl_user_students table? Is it empty? Do you have a current backup of the moodle database? You could re-import that table with a bit of SQL work if it is empty. It could also be that that table is corrupted in the database. I think there are some mysql table health checks (never used them myself) that can verify tables.
We have had a single course be emptied of students occasionally, but not all courses. We're still looking into why a single course would be emptied -- no trends yet.
We backup our database nightly with http://sourceforge.net/projects/automysqlbackup/ . We're running mysql on linux.
I wish I had better suggestions, but look at your database tables for clues.
We are currently using Moodle ver 1.5.3
with php5 version 188.8.131.52 and mysql version 4.0.24
OS is Edubuntu kernel-release 2.6.12-10-386 on an i686 Machine.