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User profile for user: T-H-D
T-H-D Author
User level: Level 1
4 points

Portable SSD formatting error (Underlying Error 6) on iMac

While trying to either format/repair/zero a relatively new Portable SSD mobile storage device I keep getting "Underlying Error 6". Can anyone advise as to how best to do this without the error?


[Re-Titled by Moderator]

iMac 21.5″, macOS 12.7

Posted on Jan 12, 2025 8:24 AM

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1 reply
User profile for user: Tesserax
Tesserax
User level: Level 10
153,384 points

Jan 12, 2025 11:13 AM in response to T-H-D

At least three things could be the reason that you are getting this error when attempting to format an external drive:

  1. Connectivity - Have you tried using another "known good" cable?
  2. Incompatible File System - If you plan on using this drive only with Macs, APFS would be the preferred choice for SSDs, or HFS+ for HDDs. If, instead, you will want to use this drive with both Macs and PC, then you should format it as ExFAT.
  3. The drive's partition table is corrupt or missing - Try using the Disk Utility's First Aid option to check for drive errors.
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Portable SSD formatting error (Underlying Error 6) on iMac

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