I'm trying to use Composer to clone the drive on an iMac (21.5-inch, Late 2013) Model A1418.
However when I plug it into my laptop via TDM with a Thunderbolt cable, the drive doesn't mount. I've disabled core storage on the volume and I see the drives in Disk Utility but all three volumes (EFI, Macintosh HD, Recovery HD) are greyed out and Disk Utility says to run First Aid when I try to mount it. Running First Aid does not detect any issues.
When I try to mount it via command line, I get "Volume on disk1s2 failed to mount: 'SUIS premount dissented'". When I Google this, I get nothing.
Has anyone experienced this issue?