Windows urbackup-service out of nowhere couldn't do backups anymore, until I restarted it

client
1

First I have to say, I’m not sure, if that post here helps in any way to find the error, since there seem to be no usable log files. anyway:
We’ve got a windows 2011 small bussiness server with urbackup client 2.0.36 running on it.
Backups worked well, until at once, about 1 or 2 weeks ago, incremental, full and image backups failed, always with one of 3 messages:

Info
02.02.17 22:08
Starting full image backup…
Errors

02.02.17 22:08
Could not read MBR
Errors

02.02.17 22:08
Cannot retrieve master boot record (MBR) for the disk from the client.
Info

02.02.17 22:08
Time taken for backing up client RMI-Windows-SBS2011: 15ms
Errors

02.02.17 22:08
Backup failed

or

Info

02.02.17 22:03
Starting full image backup…
Errors

02.02.17 22:03
Backing up System Reserved (SYSVOL) partition failed. Image backup failed
Info

02.02.17 22:03
Time taken for backing up client RMI-Windows-SBS2011: 1s
Errors

02.02.17 22:03
Backup failed

or

Info

02.02.17 22:03
Starting full file backup…
Errors

02.02.17 22:03
Constructing of filelist of “RMI-Windows-SBS2011” failed: ERR
Errors

02.02.17 22:03
Backup had an early error. Deleting partial backup.

So today I finally found time to look into it, and noticed that on the client, debug.log wasn’t updated anymore since the 16.1.2017 (that’s when the last successfull backup was made). So since then I always got error messages (only logged on the server) and the client didn’t manage to write to debug.log anymore. So I wanted to activate the log level “debug” (before we used “warn”) to see if I get something written and restarted the urbackup service on the windows machine. And since then it works perfectly again. Also debug.log is updated again.
I guess there must be a bug somewhere, but unfortunately I really can not provide you any more information than the above ones (if there is any, just ask). My best guess is that he tried to write some warnings to the debug.log, for whatever reason couldn’t write them, and because of that utterly failed, whatever he just tried or he already failed before he even couldn’t open the debug.log file.

2

Now it seems like I can do exactly one successfull backup, then the next backup fails again, and I need to restart the urbackup client service.
I activated debug logging, but there seems to be nothing interesting:

2017-02-09 10:46:22: ClientService cmd: #ImnFARJF7b2oR9kbhkaG4#2LOGDATA 1486633579 0-1486633569-Starting incremental file backup…
2-1486633569-Constructing of filelist of “RMI-Windows-SBS2011” failed: ERR
2-1486633579-Backup had an early error. Deleting partial backup.

2017-02-09 10:46:22: rc=0 hasError=true state=0

It just takes him a few seconds to fail…

any advices?
I can also send you any debug logs, setting files or whatever is necessary…

otherwise I’ll try to to deinstall urbackup client, delete everything of it I can find, and reinstall it…

3

Is the status of the client still showing to be OK or something else?

Does running the remove_unknown script on the server help you?

4

The status of the client was still showing ok.

As it seems I fixed the problem now. I stopped the client backup service. Deleted the files: backup_client.db, open_files.dat, filelist.ub. And then started the backup service again.
And now it seems to work again, at least I was able to do more than only one consecutive backup without restarting the client. I will monitor it the following days.

Probably one of those files was in a really strange way corrupted, or had some data which made the urbackup client fail after the first backup. I still think there is some kind of strange bug.
Maybe the problem was filelist.ub, the previous one was around 6MB big and the new one now is around 18MB.
I’ve copied the 3 files before I deleted them So if somebody wants to look at them to see what the problem was, I’ll upload them somewhere.