Home Forums Hardware Mac Desktops & Notebooks Single user mode problem

I periodically repair my main start up drive by running Single User Mode. The drive (two SSDs in a RAID 0 configuration) has been working fine. But the last two times I've run Single User Mode, after "Checking extended attributes file" there is a long pause, then "Failed to issue COM RESET successfully after 3 attempts. FAILING..." A hard shut down is required.

A quick Google suggests hard drive failure, but it seems to be working fine. If I boot from a clone on another drive and run Repair Disk on the drive in question, it passes.

All my software is up-to-date (10.6.8). I've run DiskWarrior. I recently ran TechToolPro to optimise the drive, which is less than half full.

I am working on the drive in question as I type, but am backing up daily...

Any ideas? Thanks.