SanDisk Portable SSD Recognition Issue on macOS Sonoma (error -69874)

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SanDisk Portable SSD Recognition Issue on macOS Sonoma (error -69874)

Hi. I have a MacBook Pro (M1 Max). There’s this SanDisk Portable SSD (2TB) which doesn’t seem to be recognised by my MacBook.

However, I can read and write to it on older Macs (Big Sur), but it doesn’t show up in disk utility on my current Mac. I know that this isn’t a problem with the SSD as it can be read by every other computer I have (macOS Big Sur, Windows 10, Windows 11).

Also, this rarely happens, but disk utility sometimes shows the disk. Although, it’s unmounted and I can’t mount it. When I try formatting it to APFS (on my current Mac), it gives an error: couldn't modify partition map -69874. Other smaller USB sticks work. This SSD used to work before updating to Ventura, but after updating, it doesn’t, and hasn't been fixed with Sonoma.

I can format it on older Macs though, but I want it to work on my current Mac. If this is a problem with my current Mac, how can I fix it?

Thanks

MacBook Pro 16″, macOS 14.5

Posted on Apr 18, 2024 10:06 AM

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Answer 1

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HWTech

Community+ 2026

Level 9

73,674 points

Apr 18, 2024 12:57 PM in response to Sidmaniac

First, make sure the SanDisk SSD's firmware is completely up to date. There were some models which had a terrible firmware issue where the data would just disappear.

https://support-en.wd.com/app/firmwareupdate

https://arstechnica.com/gadgets/2023/05/sandisk-extreme-ssds-keep-abruptly-failing-firmware-fix-for-only-some-promised/

https://arstechnica.com/gadgets/2023/08/sandisk-extreme-ssds-are-still-wiping-data-after-firmware-fix-users-say/

Second, when you erased the external SSD, did you erase the whole physical drive? Within Disk Utility you may first need to click "View" and select "Show All Devices" before the physical drives appear on the left pane of Disk Utility. Make sure to erase it as GUID partition type and whatever file system you wish (MacOS Extended, APFS, or exFAT.....depends on what other operating systems will need access to the SSD).

Erase and reformat a storage device in Disk Utility on Mac - Apple Support

Make sure to connect the SSD directly to the computer. Disconnect all other external devices in case one of them is causing a problem.

Try booting into Safe Mode to see if you have better luck with the SanDisk SSD....assuming you are not using any third party software to manage the Sandisk SSD.

Try using a different USB cable & adapter.

Perhaps the SanDisk SSD has a hardware issue....some computers and operating systems may be pickier about a hardware issue than others.

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