Time Machine: still failing

The highest-traffic page on Mac Me Up (with a hit count four times its closest rival) is “Time Machine: Backup failed with error: 11”, which I wrote just over nine months ago. In the interim, I bought a Time Capsule, and things have been going fairly smoothly. Until yesterday. A Time Machine backup failed on the Mac Pro, and I ran into my old friend Error 11.

The symptoms this time were different to those I reported in January. backupd seemed to be complaining about an inability to move a single file: a preference list in ~/Library/Preferences. (Being unable to copy a single file, of course the entire backup failed. How robust.) I don't have the log handy to cut and paste, but that's not a big deal since the log adds essentially no useful information whatsoever, and certainly nothing resembling a cause for the copy failure. Just our old friend, Error 11.

I deleted the file (it was for a trial version of an Aperture plug-in), and then Time Machine complained about another one in the same directory. I moved the directory onto Time Machine's ignore list, and the backup completed fine. I'm not buying the idea that this is a disk failure or pre-failure. There is no other evidence of disk trouble. There is no SATA-subsystem logging of read or write errors. System Profiler lists the S.M.A.R.T. status as "Verified". Before I deleted it, I opened and viewed the file.

Time Machine needs to be fixed.