I have a late 2012 iMac. Recently I noticed a hand full of my image files were corrupted. I ran First Aid and it told me that “Underallocation detected on tier2 device”. It wouldn't complete though, it would freeze.
I wound up copying my hard drive to an external disk, and then formatting my iMac hard drive and reinstalling MacOS. I restored the system to an old backup (mid-2017) and have since been going through my external drive to see what's recoverable and what's messed up.
However, my question is what causes an Underallocation error? At the time I noticed the data corruption, I only had around 180GB left of space on my 3TB drive. Did I let my drive fill up too much? Is this a software problem, or is this hardware related? What can cause this?
Since reformatting, everything seems ok, though I'm only using around 1.5TB of space. I'm debating updating to 2019 iMac, but I kind of want to better understand why this happened. Anyway, thanks for any responses.
I wound up copying my hard drive to an external disk, and then formatting my iMac hard drive and reinstalling MacOS. I restored the system to an old backup (mid-2017) and have since been going through my external drive to see what's recoverable and what's messed up.
However, my question is what causes an Underallocation error? At the time I noticed the data corruption, I only had around 180GB left of space on my 3TB drive. Did I let my drive fill up too much? Is this a software problem, or is this hardware related? What can cause this?
Since reformatting, everything seems ok, though I'm only using around 1.5TB of space. I'm debating updating to 2019 iMac, but I kind of want to better understand why this happened. Anyway, thanks for any responses.