External hard drives do not mount after Tahoe upgrade
External hard drives do not mount after Tahoe upgrade
Question marked as
Finder menu > Settings > General tab, tick the box to show External Disks. Change the same setting on the Sidebar tab, if you like.
If those boxes are already checked, then open Applications > Utilities > Disk Utility, select View menu > Show all devices. Does it show up there, and if so, can you mount it?
If you have a Mac laptop computer (not applicable to Mac desktops), accessories must be allowed to connect. Go to System Settings > Privacy & Security > Accessories, try changing it to Automatically allow when unlocked or Always allow.
If you have 3rd party ‘protection’ software installed, that may be the problem. For example, ESET has been reported to prevent external drives and memory cards from mounting. Such 3rd party system ‘helpers’, ‘cleaners’ and ‘protectors’ do more harm than good. In fact, such products are completely unnecessary for macOS and the only ‘good’ (if you want to call it that) they do is to put money in the developers’ pockets. For the user, they offer only harm…and if that is limited to harm to your bank account, then count yourself lucky.
There were a few prior posts on this forum from users who couldn’t access their external drive due to the drive manufacturer’s software that they used to encrypt the drive. Lacie/Seagate, Samsung, SanDisk, etc., all provide 'drive management' software on their drives and using such 3rd party software can cause issues when macOS is updated and the 3rd party software becomes incompatible. Not sure if that's the issue here, but FYI the best practice with a new external drive (SSD/HDD, not applicable to NAS drives) is to use Disk Utility to complete erase it, format it as GUID/APFS and apply encryption if desired.
If your drive is using a FireWire connection, it will not work anymore because starting with macOS 26 Tahoe, FireWire has been fully deprecated by Apple and is no longer supported.
FWIW, I have a bunch of Samsung T7 SSDs ranging from 1 TB to 4 TB, and a pair of 8 TB Crucial SSDs, and they all work fine with my M4 Pro MacBook Pro running Tahoe. Older LaCie HDDs (500 GB to 5 TB) also mount fine on Tahoe.
Final note: if nothing at all is showing on your Desktop, go to System Settings > Desktop & Dock and make sure the box to Show Items On Desktop is checked.