4TB Drive Shows As 1.8TB


Mac OS 10.10.5
Early 2009 Power Mac
G/Drive Enclosure #F30S2JAD GD4 2000 (Originally 2TB)

The 2TB drive failed in my out of warranty enclosure, so I installed a WD Enterprise 4TB.
Hooked up via FW800, or USB 2.0, the drive showed as 1.8TB in Disk Utility when I tried to initialize/format it.
I used a raw drive USB hookup and it showed as 4TB and I was able to initialize/format it, no problem.
Back into the G/Drive enclosure and the drive was formatted & named, but still showed as 1.8 TB.

I tried a Mercury enclosure via FW800 and it also showed 1.8TB.
When I ran disk utility repair, it showed “partition map check failed because no slices were found”.
This was the same when in the G/Drive & Mercury enclosures.

Thoughts? Thanks.


Those old enclosures won’t support over 2TB due to LBA48 support. The old tech in them won’t allow larger than 2TB capacity.



Thanks for clearing that up!