Time Machine will not complete a system backup and terminates with "Unable to complete backup. An error occurred while copying files to the backup volume. This follows a problem when Time machne terminated when the volume was almost full.

Question

On 11/1/2011, Time Machine (TM) terminated with an error message I did not record.  I noted that the drive was full and decided to do a separate complete bootable  system backup using Carbon Copy Clone (CCC), before clearing the TM volume and trying to start it over clean.  Part way through the full system backup CCC put up a message that there was a Physical Problem  "Library/Application Support/Techtool Protection/McIntosh HD/Directory Backup 2011-11-01-16-28-16".  That was about the time that TM malfunctioned, so I assumed they were related.  After starting CCC over a couple of times, and getting the same error message, I let it go through to completion of the backup, which took three or four hours.  I then ran tests using Disk Utility and verified that there was nothing physically wrong with both the internal hard drive and the TM volume.  I also erased and reformatted the TM volume.  However, every time I started Time Machine, it would record a few GB and terminate with "Unable to complete backup. An error occurred while copying files to the backup volume".  I restarted the computer with no change in results.  Note that prior to starting the CCC backup, I "Repaired Permissions", "zapped the PRAM" and "re-set the SMC", hoping to have a clean bootable system on the backup.  I ran Techtool and no problems were found.
I'm running this on an Intel iMac under 10.5.8 and recording to a 500GB My Passport drive.  My hard drive is only about half full at 246 GB.  My assessment is that something happened at 16-28-16 on 11/1/2001 to screwup the Backup Directory in the file at "Library/Application Support/Techtool Protection/McIntosh HD/Directory Backup 2011-11-01-16-28-16". My question is, how do I fix it?
I had just completed writing everything above here, explaining the problems I had been encountering for the past 24 hours.  I had the Time Machine window standing open on the desktop where I could see it, having recentlycleared it after the last termination.  As I was proofing what I had written, I looked at the window and noted that the clock had started a new run for a full back up, since all prior efforts had failed and the TM volume was empty.  As I watched and waited for it to fail again, as it had been doing at about 13 GB, it kept going and going until it just finished a complete backup, about 4.5 hours later, with my having done nothing.  Now my question would have to be - what could possiibly have happened to make it perform this way?   It will be interesting to see if it continue to operate normally, or if the problem will return, in a later backup run.

Answer 1

jcm21 wrote:
CCC put up a message that there was a Physical Problem  "Library/Application Support/Techtool Protection/McIntosh HD/Directory Backup 2011-11-01-16-28-16"
You should not keep those files for long, and probably shouldn't back them up (if you need them at all -- since you do regular backups, I'm doubtful just how worthwhile that feature is).
"Unable to complete backup. An error occurred while copying files to the backup volume".
One of Apple's maddeningly incomplete messages. Most likely, there's a problem with a file (quite possibly the one CCC didn't like).  See #C3 in Time Machine - Troubleshooting for details and instructions on finding and fixing it.
If you continue running the Directory Protection app, be sure to exclude your Time Machine drive from it (as it will just take up lots of room, and won't help repair your backups if there's a problem);  and exclude the folders it creates from being backed-up by Time Machine (as they'll create large backups, and you probably can't use the backed-up folders anyway), per #10 in Time Machine - Frequently Asked Questions.