macOS Tahoe fails to mount external drives

Mac Tahoe won't mount external drives.


[Re-Titled by Moderator]

Original Title: external drives

MacBook Pro 16″, macOS 26.0

Posted on Sep 20, 2025 10:29 AM

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Posted on Sep 29, 2025 1:15 PM

Solved! This happened after upgrading to 26.01


I went to Settings > Privacy and Security > Scroll to the bottom for Accessories and changed it from "Always Allow" to "Always Ask" I replugged my External Disks and I was asked to "Allow Accessory" Clicked ok and now it works.


Then I reset the Preference back to “Always Allow” Accessories.


Restarted and all of my Drives mounted.

13 replies
Question marked as Top-ranking reply

Sep 29, 2025 1:15 PM in response to bphillips1062

Solved! This happened after upgrading to 26.01


I went to Settings > Privacy and Security > Scroll to the bottom for Accessories and changed it from "Always Allow" to "Always Ask" I replugged my External Disks and I was asked to "Allow Accessory" Clicked ok and now it works.


Then I reset the Preference back to “Always Allow” Accessories.


Restarted and all of my Drives mounted.

Oct 16, 2025 8:03 AM in response to Vincent Scarafino

I did all these steps and still it is not possible to mount the external volumes. Neither the FileVaults encrypted once (Backup Volume for Carbon Copy Cloner) not the APFS Encrypted once nor the APFS unencrypted once.


I change the Privacy and Security settings multiple times and rebooted the MacBook Air M3 every time afterwards.


If I connect my drives to my Mac mini M1 still running on MacOS 15, everything works fine.


Any idea what else I can change / try?

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macOS Tahoe fails to mount external drives

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