I can no longer use external storage on my MacBook Pro M4 Max after installing the new Tahoe Ver 26

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Level 1

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I can no longer use external storage on my MacBook Pro M4 Max after installing the new Tahoe Ver 26

Hello everyone!

I have a problem: I can no longer use external storage on my MacBook Pro M4 Max after installing the new Tahoe (Ver. 26). When I plug in my USB drive, Finder asks me to authorize its mounting, but it doesn't. I also can't use any memory stick or other USB flash drive. Before that, everything worked perfectly.

When I open Disk Utility, I see a light gray message with the name of my USB drive, but I can't open it.

I've tried all the Terminal commands I found on websites, but nothing helps. I've formatted it, tried all possible formats on all my USB devices, but the situation is the same.

I've also tried setting Accessories in Settings to ask if I can use the USB drive every time I plug it in, and then to always use it without asking, but the situation is the same.

Perhaps someone else encountered this problem after the update?

And most importantly, if someone has a solution, please share it with me.

Thanks.

MacBook Pro 14″, macOS 26.0

Posted on Oct 27, 2025 10:24 AM

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Answer 1

Top-ranking reply

neuroanatomist

Level 9

55,905 points

Oct 27, 2025 10:27 AM in response to jlurzua

Not the first report of this I've seen, though I routinely use my M4 Pro MBP with a bunch of external SSDs.

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.

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Answer 2

Phil0124

Level 10

216,950 points

Oct 27, 2025 10:42 AM in response to jlurzua

How are these drives formatted exactly?

I use a number of external drives with my M1 MacBook Air on Tahoe and they all work fine.

Were you using an NTFS driver like Tuxera or Paragon to access Windows formatted drives?

If so, you may need tp update the driver.

If you are using the drive manufacturer's encryption software, it may also require an update.

Do the drives appear in Disk Utility when connected?

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