Can't upgrade from Ventura to Sonoma: 'The volume cannot be downgraded'

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Level 1

7 points

Can't upgrade from Ventura to Sonoma: 'The volume cannot be downgraded'

The disk to install to is greyed out and when clicked on it says 'The volume cannot be downgraded'. Which is of course weird because I'm actually upgrading.

I also tried to do it via a USB bootable Sonoma installer but I get the same message and a greyed out disk.

NOTE: When trying to upgrade to Sequoia I don't get the the message (drive is also not greyed out), but with a relatively older Mac I'd rather have one OS version earlier (I'm probably being overly cautious, but it is what it is).

Any ideas?

Macbook Pro 2018 running Ventura 13.7.1

MacBook Pro (2017 – 2020)

Posted on Jan 28, 2025 7:06 AM

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Answer 1

Top-ranking reply

Luis Sequeira1

Level 9

73,254 points

Jan 28, 2025 7:15 AM in response to MexVector

It does look like you may have unwitting installed Sequoia on this drive.

Start your mac, and from the Apple menu choose About this Mac.

Post a screenshot of what you get (not including the Mac's serial number, that is considered private information).

Something like this (as you can see, my mac is running Sequoia 15.2)

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Answer 2

MexVector Author

Level 1

7 points

Jan 29, 2025 4:27 AM in response to MexVector

Managed to install Sonoma the 'normal' way. This was after I updated from Ventura 13.7.1 to 13.7.3.

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Answer 3

HWTech

Level 9

68,702 points

Jan 28, 2025 9:47 AM in response to MexVector

Try a DFU Firmware Revive which resets the T2 security chip & system firmware. Unfortunately this requires access to another Mac most likely running macOS 15.x Sequoia.

Just make sure to have a good backup first just to be safe even though the "Revive" process should not affect the data....I don't know what happens if the "Revive" process does not complete successfully.

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Answer 4

MexVector Author

Level 1

7 points

Jan 28, 2025 7:48 AM in response to Luis Sequeira1

Hi Luis,

Here you go:

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