updated 06:24 pm EST, Tue February 26, 2013
Permissions glitch appears to be cause of recovery problem
An apparent issue with permissions on the recovery partition of recent Macs -- those that shipped with Mountain Lion pre-installed -- can make it very difficult to reinstall Mountain Lion in the case of system corruption on the boot drive. The problem even affects trying to restore Mountain Lion from a Time Machine backup, and falsely reports that the Mac in question "isn't compatible with Mountain Lion." Thanks to a support forum thread on Apple's website, a workaround has been found: repairing permissions on the recovery partition.
The bug prevents users from re-downloading the OS X Mountain Lion installer from the Mac App Store, or using a pre-existing copy a user may have saved from a previous install. The problem suggests that a "compatibility check" type program is also part of the glitch, however at least repairing permissions on the recovery partition appears to allow restoration from the partition, reports MacTrast. Once the OS X recovery is complete, users can then use Migration Assistant to recover user data from Time Machine backups rather than the now-blocked direct recovery of the system and apps from Time Machine.
This isn't the first time that 2012 Mac owners have had issues with the download-only-based Mountain Lion: Apple was forced to issue an update to those machines to allow them to upgrade to 10.8.2 if they shipped originally with 10.8.0 or higher. It's possible that the new problem is related in some way to the previous one (which involved a bug in Keychain), and also possible that the problem will be resolved in the release of 10.8.3, which has been in testing for four months and achieved an unusual number of betas prior to release.
While the problem itself is perplexing, users can take comfort that the need to completely reinstall Mountain Lion from a un-crashed but corrupted hard drive is still very rare, making it likely that the bug will be resolved long before most users ever need to take advantage of it. In the meantime, a recovery partition-based restore of Mountain Lion that is preceded by a permissions repair of the partition should allow the reinstall to proceed.