Shirt Pocket Discussions

Shirt Pocket Discussions (
-   General (
-   -   Error 18 in Time Machine.... (

iith096 10-20-2008 12:43 PM

Error 18 in Time Machine....
Hello all,

Recently I have been having a problem getting my Time Machine backups to complete. I continue to receive the following error in the system.log:

Oct 20 09:32:25 admins-mac-pro /System/Library/CoreServices/backupd[14338]: Backup failed with error: 18
Oct 20 10:32:20 admins-mac-pro /System/Library/CoreServices/backupd[14419]: Starting standard backup
Oct 20 10:32:20 admins-mac-pro /System/Library/CoreServices/backupd[14419]: Volume at path /Volumes/Drobo Backup does not appear to be the correct backup volume for this computer. (Cookies do not match

My current backup strategy is:

2.8ghz Quad Core Mac Pro, 8GB Ram, 3 internal hard drives.

1: Boot: 500GB WD Green Drive.
2: Super Duper backup drive. 500GB WD Green Drive. This is doing a daily backup mirror of my first boot drive above.
3: 1TB WD Green Drive which holds my Time Machine backups along with backups of the contents on my external Drobo disk array. Currently, 500+GB of data out of a total 2TB of space.

Every night in addition to the daily Super Duper backup of my boot drive to the second internal hard drive, I also do a backup of the contents on my external Drobo disk array to my third internal hard drive. As stated, my Time Machine backups are also saved to this third internal drive along side with my other data.

All backups work as requested with zero errors. However, every morning exactly after my Drobo backup completes, my Time Machine backup begins to fail with the same "error 18" error. I have to manually "remove" my existing Time Machine disc selection in settings and then re-choose it again and my Time Machine backups start up again with no further problems.

Has anyone else seen this error? Any luck resolving it? Per the Super Duper help files, it states that I can have Super Duper backup to and save my data along with an existing Time Machine backup and Super Duper preserves it.

Thanks all for your help and sorry for the long post.


dnanian 10-20-2008 12:47 PM

I haven't seen this myself, no. Are you backing up your Time Machine backup itself?

iith096 10-20-2008 01:02 PM

No. But some back history.

Originally, Time Machine was saving its backups to the external Drobo disk array along side with my other data. Super Duper would do a nightly backup of the entire Drobo disk array contents to the internal hard drive without any problems to either Time Machine or Super Duper. However, due to the constant access and fan noise on the Drobo, I redirected Time Machine to perform its hourly backups to the internal 1TB WD hard drive instead and I manually deleted the existing Time Machine backup data on the Drobo to free up some space.

Ever since then, I now get an "error18" in the logs in regards to Time Machine.

Is it possible that there is some "hidden" remnants (or cookies as stated in the error logs) of the previous Time Machine backup data still on the Drobo that Super Duper is seeing and re-writing back to the internal disk which is tripping up Time Machine into thinking the disk is not the correct backup location?


dnanian 10-20-2008 01:22 PM

OK. There are various cookies that Time Machine leaves on the volume: has nothing to do with SD. Try using Disk Utiltiy to erase the Drobo volume you had Time Machine on originally, rather than just erasing the TM data you can see.

iith096 10-20-2008 03:57 PM

Thanks for your prompt replies.

I think I am going to disable Time Machine all together and just rely on Super Duper to keep backups.

Thanks again.

All times are GMT -4. The time now is 04:02 PM.

Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2021, vBulletin Solutions, Inc.