My 1 TB passport is not recognised on my iMac anymore, but is recognised on my Powerbook Pro.
I initially formatted the drive in FAT32 so that it would be recognised by PC and MAC and have used it for years on MACs and PCs with no problems
All other PCs and computers still recognise the drive, except for the iMac. The iMac OS has recently been updated to Yosemite but so has the Macbook pro, which can still access the drive.
Any ideas please?