Unmounted external SSDs and SD card not showing in Finder or Time Machine on iMac

Hi, just installed Tahoe on my 2020 i7 imac, but only 1 external SSD is showing up in finder, not even the sd card slot, i can see them in Disk Utility which shows them Unmounted, but will not mount, can anyone help please ?

No accessible drives show in Time Machine either



[Edited by Moderator]

iMac 27″, macOS 26.0

Posted on Oct 10, 2025 2:35 AM

Reply
1 reply

Oct 10, 2025 8:27 AM in response to davidjames1701

Sorry, I should have worded that better -


Hi, just installed Tahoe on my 2020 i7 iMac, but no external drives will show up in finder under Locations, inc the SD card reader, they all show in Disk Utility as unmounted, if I right click on any and select Mount, nothing happens, only 1 drive can be read in Finder, not in locations, but tagged in tags, I've tried First Aid in Disk Utility, Time Machine doesn't recognise anything, all drives are instantly recognised on my old 2013 MacBook Pro running Big Sur, any help would be very appreciated thanks

Unmounted external SSDs and SD card not showing in Finder or Time Machine on iMac

Welcome to Apple Support Community
A forum where Apple customers help each other with their products. Get started with your Apple Account.