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Install MacOS Tahoe on external SSD

Hello,

I am trying to install MacOS Tahoe on an external SSD to test my applications before updating my MacOS Sequoia. The external drive is correctly formatted (at the root of the physical drive). The installation does not complete! After the second restart, I am back on my Sequoia! When I try to continue the installation, my external SSD displays the following message: this volume cannot be used because it has a secure token without a user.

Thank you for your help.

MacBook Pro 14″, macOS 15.7

Posted on Oct 30, 2025 3:51 AM

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HWTech

Level 9

68,690 points

Posted on Oct 30, 2025 12:50 PM

You also need to erase the whole physical drive so that the partition table is rebuilt as well since sometimes the partitioning from the factory can cause problems (especially when used as a boot drive). See the following Apple article from the Internet Archive since Apple has changed & ruined the most recent version of the article:

https://web.archive.org/web/20250909095655/https://support.apple.com/guide/disk-utility/erase-and-reformat-a-storage-device-dskutl14079/mac

You are not using the proprietary Samsung software to manage that T7 SSD are you? If you have enabled the T7's builtin hardware encryption, then that can be a problem as well.

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26 replies

macdan67 Author

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Nov 1, 2025 2:46 AM in response to HWTech

Thank you for all these ideas. I just tried again with a Crucial X8 SSD. I have never enabled a hardware encryption on this device...

First, I erased the whole physical drive.

I have selected the correct USB port (not DFU). On MacBook Pro M4, the DFU port is on the right side...

As you suggested, I tried another USB-C cable (from Apple).

No other device was connected.

The result is the same: the installation does not complete. After restarting, I once again see the Sequoia welcome screen on my Mac (my current OS).

Do you know of a compatible external SSD drive model for booting?

Thank you for your help!

macdan67 Author

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Nov 1, 2025 4:03 AM in response to Ian R. Brown

Thank you! But I'd prefer not to touch the internal drive...

Finally, I think there's another problem. I tried again with a standard external drive (USB-C, not SSD), but that doesn't work either! When I try to continue the installation, I can no longer select the external drive. I get the following message: this volume cannot be used because it has a secure token without a user.

It's the same with both SSD drives I tried.

Any other ideas to avoid this message?

macdan67 Author

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Nov 1, 2025 3:42 PM in response to Ian R. Brown

Thank you! I formatted the drive as you instructed. And I chose the right port.

I also tried installing Sequoia on the external drive first, thinking I would upgrade to Tahoe later. But I couldn't install Sequoia either! I even called Apple support: I was on the phone with them for an hour, but they couldn't give me a solution. Well, they did give me one: see if anyone I know has a recent Mac with Tahoe and try my external drive on their computer...

I think the only solution will be to try on my internal drive...

It seems impossible for me to install an OS on an external drive from my MacBook Pro M4...

macdan67 Author

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Nov 5, 2025 11:59 AM in response to PSolt

Thank you for your message.

I made sure to use the correct port on the 14-inch MacBook Pro. According to Apple Support, the DFU port is located on the right side of this model.

So I plugged my SSD into one of the USB-C ports on the left. side...

HWTech

Level 9

68,690 points

Nov 5, 2025 4:43 PM in response to macdan67

macdan67 wrote:

Thank you for your message.

I made sure to use the correct port on the 14-inch MacBook Pro. According to Apple Support, the DFU port is located on the right side of this model.

So I plugged my SSD into one of the USB-C ports on the left. side...

Please take a picture of your laptop & mark the picture showing the USB-C port you think is the DFU Port. I think you are misreading Apple's instructions. The front left USB-C Port is the DFU Port on your Mac.

AFAIK, all DFU ports on all Apple laptops 2018-2024 are on the left side of the laptop......some are the back port & some are the front port.

macdan67 Author

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Nov 6, 2025 2:10 AM in response to HWTech

You did well to insist to give me the correct information! I have finally understood!

It must be said that it is not very clear even on Apple Support...

The rightmost port when you look to the left! It would be better to have an illustration! For non-English speakers, this is not easy!

And I have just found the Apple support article in French...

Finally thanks to you I can try again by connecting the SSD to the correct USB-C port!

Thanks again!

Daniel

HWTech

Level 9

68,690 points

Nov 6, 2025 6:26 AM in response to macdan67

macdan67 wrote:

You did well to insist to give me the correct information! I have finally understood!

It must be said that it is not very clear even on Apple Support...

The rightmost port when you look to the left! It would be better to have an illustration! For non-English speakers, this is not easy!

Must have been an unpaid & unsupervised intern crafting that article, or perhaps they used AI to create it, or someone devious who just loves to make things complicated. After all, why not randomize the location of the DFU ports instead of standardizing on a single port location. After all I thought Apple designs & controls everything about their products...why the refusal to standardize? It does reveal something about the internal culture at Apple.

You can provide feedback to the Apple article.....the feedback link/button is located at the bottom of each Apple article.

And I have just found the Apple support article in French...

Finally thanks to you I can try again by connecting the SSD to the correct USB-C port!

Thanks again!

Daniel

You're welcome. Please let us know how you make out with it.

macdan67 Author

Level 1

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Nov 6, 2025 9:37 AM in response to HWTech

The problem remains the same! I tried again to install Tahoe on the external SSD (Crucial X8), this time connecting it to the only USB-C port on the right side of the MacBook Pro, which should be OK, I guess! But the installation doesn't complete, just like before...

On my MacBook Pro, I'm now running macOS 26.1 and everything is working fine. I also know now that I can install a second OS on a partition of the internal drive if I want to test something…

But I'd still like to know why I can't install an OS on an external drive! Even if I don't need it right now...

When I try to continue with the installation, I always get this message about a secure token!

macdan67 Author

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Oct 30, 2025 10:03 AM in response to HWTech

Thank you! I was careful not to connect the drive to the DFU port...

macdan67 Author

Level 1

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Oct 31, 2025 10:27 AM in response to macdan67

I tried with another external SSD drive: the problem is the same. Tahoe won't install. For me, it only works with a normal 2.5-inch external drive (not SSD)! Any ideas for the SSD? Thank you.

macdan67 Author

Level 1

10 points

Nov 2, 2025 1:09 AM in response to HWTech

Thank you! I will take my Mac and the external drive to an Apple Store...

Install MacOS Tahoe on external SSD