SanDisk Portable SSD Won't Format on Mac Error -69874

General
1

My MacBook Pro (M1 Max) doesn’t recognize a SanDisk Portable SSD (2TB) that works on older Macs running macOS Big Sur or Windows PCs running Windows 10 or Windows 11.

Sometimes, it shows up in Disk Utility. When it does, I try to format it to APFS, but it fails with the error “couldn’t modify partition map -69874.” How to recognize the SSD on my MacBook Pro?

2

Did the problem occur after a macOS update?

If so, you need to update the SanDisk SSD’s firmware. SanDisk has identified an issue with their SanDisk Extreme Portable SSD V2, SanDisk Extreme Pro Portable SSD V2, and WD My Passport SSD products, which quit unexpectedly, and recommends updating the firmware as a solution.

3

When you reformat the SSD, erase the physical drive instead of the partition. Here’s how:

  1. In Disk Utility, click View > Show All Devices.
  2. Then select the top-layer physical drive and click Erase.
  3. Choose APFS as the format.
  4. Choose GUID Partition Map as the scheme.
  5. Click Erase.

If it continues to fail with error 69874, try a different format, such as exFAT or FAT32.