Will not boot into Safe Mode

I can confirm that 'Apple memory' does seem to have a factor in this for some folks.

I too have been plagued by this safe mode hung trouble. I was asked to try some actions in Safe Mode by Apple support for an unrelated issue when I stumbled across this non-booting-into-safe-mode behavior.

In my case I'm running 10.7.5. Tried safe-mode booting multiple times - no luck. Ran diskutility several times - no difference. Rebooted into single-user mode and manually fsck'd the harddrive - still no improvement or progress beyond the 'extended attributes' examination step.

I finally dug out my original memory, removed all my RAM, and installed a single 2G stick of the mem that came with the system - Safe Mode finally booted just fine.

The memory thing is a red herring. Every machine I have with this problem is bog stock from Apple. The cause has already been wsuccessfully diagnosed way back in this thread as a fault with Apple's fsck.

Is it OS X 10.9.1 (Mavericks) on all Macs that you now find affected?

I'm having this same issue, any conclusive answers?