An external drive connected to a Mac.
Some Mac users are finding they can’t use their external drives with macOS Tahoe 26.3, and it seems Apple knows something is wrong. Let us know what works for you and what doesn’t.
Apple released an update to macOS Tahoe 26.3 on February 11, with the update adding more machine learning power to M5 users as well as other minor changes. It seems that one undocumented change may have caused problems for some users.
A number of users have taken to online support forums and social media to try and get help with their external drive issue in macOS Tahoe 26.3. Affected users find that external drives do not connect properly, even though they previously worked fine.
Tea AppleInsider The editorial team has also encountered the issue, with some noting problems mostly with SSDs. In the case of our cameraman, the drives he uses on a daily basis occasionally malfunction when connected, with read and write speeds sometimes dropping to several megabytes per second and forcing reboots.
Other accounts we’ve seen are more serious failures. The drives just won’t mount completely.
I opened my laptop, plugged in my Samsung T7 SSD (which has every single video file I’ve ever made and is the only place they are) and this is what came up. I don’t know what to do. Hopefully it’s as simple as moving these files to another drive. But I’m kind of scared. pic.twitter.com/5je2xg34jx
— tyler (@tylerdotmp4) February 20, 2026
Another example of the problem is demonstrated in the screenshot on X, which shows a window warning “macOS cannot repair the disk”. In this case, the disk could be read but could not be written to unless the user reformatted it as instructed in the message.
The relatively few cases of publicly visible complaints mean that this is a problem experienced by only a small number of users. It’s also not clear what exact disk configurations are affected, in part because visible complaints leave out this kind of crucial information.
The Twitter complaint mentions a Samsung T7 SSD that connects via USB-3.2 Gen 2.
There is no real solution in sight for those affected.
Past and future
This is not the first time that Apple has dealt with disk issues in macOS 26. Already in the initial developer betas for the first release of macOS Tahoe, there have been complaints about the external disk not showing up on the macOS desktop.
This issue appears to have been resolved in a later update. However, based on current reports, it may be that the same issue or something similar has appeared in the latest updates.
It also appears that this is an issue that Apple is already aware of.
There are two known issues related to external drives in the release notes for the first developer beta of macOS Tahoe 26.4.
The first is when using an external drive to boot some M1 Mac configurations, such as “boot panic”. The workaround is to install on a secondary volume in an APFS container instead of an external drive.
The second explains that external HFS media “may not automatically mount”. Apple recommends that Mac users use the discutil terminal tool to mount the drive instead.
This second listing is close to the current issue of 26.3, except that it is not limited to HFS. In the case of our own issues, we found that this also happens on drives that are formatted in APFS.
The beta release also affects users in a similar way, with one post on Reddit describing the same pop-up under macOS 26.4 as under 26.3.
At this time, there does not seem to be a way for users to resolve this issue. Plus, it doesn’t seem like a widespread enough problem for Apple to be proactive about a solution with any urgency.
Bringing the situation to Apple’s attention through their support channels will help raise awareness and get Apple to work on the problem.
If this applies to you or not, please leave a comment below about your specific drive setup. Please specify which Mac, which drive and which interface you are using. Alternatively, email us directly with your details.
Maybe a solution can be found before Apple comes out with a fix.