Mountain Lion 10.8.3 cannot restore

This is curious.
So I made a boot USB, wiped my drive in my rMBP and installed 10.8.3. All was fine until I wanted to tell OSX to get all my files from my Time Machine backup. Neither the installer nor Migration Assistant want to use the backup created just a short while before. Luckily it is available on both my time capsule and another FireWire drive, so I'm sure it's good.

Both the installer and Migration Asssistant can see time capsule but just pause (not hang, but not do anything either) when I select it as a device. As for the FireWire drive, it shows up in the recovery partitions 'restore from backup' feature and on the desktop, but it will not show up in any form of migration (in the installer or in Migration Assistant).

Now have tried the installation of 10.8.3 several times, and tried restoring from several devices including USB. In a nutshell, anything to do with Migrating cannot see any form of drive...

I've never bad this before, done the same process since leopard and never bad this.
I'm gonna try re downloading the installer and making a new USB boot drive to see if something went wrong there.

Any advice really welcome!

Mmm, so contacting Apple and more experimentation resulted in finding out that somehow Time Machine in 10.8.2 had made kind of duff backups. All the files were usable but two completely separate backups, on two different mediums, were not usable by Migration assistant.

Manual restore required from said backups.

Googling around this problem is averagely common and goes back way before Mountain Lion. What could these backups be missing to make them no good for Migration Assistant? Makes me wary about using the system in the future.

FYI these were clean backups that had only ever been part of 10.8.2, so nothing especially complex about them.