So my girlfriend's Mac Pro (Mid 2012, Catalina, SANDISK Ultra 3D SSD 512GB as boot drive) suddenly gave in today. On boot it would only display the directory symbol with a question mark within.
Rebooted in recovery mode, diskutils told me the disk had to be repaired, but repair would fail with "Partition map check failed because no slices were found".
Some googling later stuff like this How to fix broken GPT, GUID and unmountable, no type volumes? and Apple forum: disk0s2 can't mount - Partition shows as "MBR part 255" pointed me to gpt and fdisk.
gpt output:
-bash-3.2# gpt -r show /dev/disk0
start size index contents
0 1 PMBR
1 1 Pri GPT Header
2 32 Pri GPT Table
34 409606
409640 999805536 1 GPT part - 7C3457EF-0000-11AA-AA11-00306543ECAC
1000215176 7
1000215183 32 Sec GPT table
1000215215 1 Sec GPT header
fdsk output:
-bash-3.2# fdsk /dev/disk0
Disk: /dev/disk0 geometry: 62260/255/63 [1000215216 sectors]
Signature: 0xAA55
#: id cyl hd sec - cyl hd sec [ start - size]
1: EE 1023 255 63 - 1023 255 63 [ 1 - 1000215215] <Unknown ID>
2: 00 0 0 0 - 0 0 0 [ 0 - 0] unused
3: 00 0 0 0 - 0 0 0 [ 0 - 0] unused
4: 00 0 0 0 - 0 0 0 [ 0 - 0] unused
Comparing my gpt output with others I noticed the first partition (start at 40, length of 4090600, probably the partition table?) is missing. So I followed aforementioned links and tried destroying and re-adding the existing part, followed by diskutil:
gpt destroy disk0
gpt add -i 2 -b 409640 -s 999805536 -t 7C3457EF-0000-11AA-AA11-00306543ECAC /dev/disk0
diskutil repairDisk disk0
Which only changed the directory symbol with question mark on startup to a stop sign (did I do a whoopsie?).
Afterwards I tried adding the first partition as well:
gpt destroy disk0
gpt add -i 1 -b 40 -s 409600 -t C12A7328-F81F-11D2-BA4B-00A0C93EC93B /dev/disk0
gpt add -i 2 -b 409640 -s 999805536 -t 7C3457EF-0000-11AA-AA11-00306543ECAC /dev/disk0
with and without: diskutil repairDisk disk0
But same result. Now I'm out of ideas. Anyone got some?
