Why does my 4 TB SSD not mount automatically on my M1 iMac?

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Level 1

23 points

Why does my 4 TB SSD not mount automatically on my M1 iMac?

I have two Crucial brand SSDs connected via USB to my 2021 M1 iMac running Sequoia 15.0.1. When I restart my computer, the 1 TB SSD automatically mounts, but the 4 TB SSD that I use for Time Machine backups does not. If I disconnect the cable and plug it back in, it mounts just fine and handles Time Machine backups just fine.

The 1 TB SSD that mounts is formatted APFS, while the 4 TB is formatted APFS (case-sensitive, encrypted). The only other difference I can find is that the 1 TB SSD has Owners disabled, while the 4 TB SSD has owners enabled.

Crucial tech support wants me to reformat the SSD to be straight APFS. If I were to do this, I believe reformatting would cause all the data to be lost (3.69 TB). I really don't want to do that if I can avoid it.

Is there another approach?

[Re-Titled by Moderator]

iMac 24″, 15.0

Posted on Oct 9, 2024 2:55 PM

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Answer 1

Norway 4 Author

Level 1

23 points

Oct 20, 2024 9:31 AM in response to Norway 4

I worked with Crucial to troubleshoot this issue. Ultimately, I was asked to wipe out the 4TB SSD and reformat it as APFS as opposed to APFS (Case-sensitive, Encrypted). It did not work. The SSD would still not automatically mount after a system reboot. The final step was to send the SSD back to Crucial for a replacement. I can update this question once I receive the replacement.

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