Tahoe Time Machine Failure on Samsung T7
ISSUE
Every good storage failure starts innocently.
Plug in a brand-new Samsung T7.
Select it in Time Machine.
Click “Use Disk.”
Allow macOS to format the drive automatically.
Let the backup run. It may even complete once — maybe even a few more times.
Then it fails with a generic error:
“An error occurred while preparing the backup.”
Time Machine consistently failed during the “Preparing backup” phase on macOS 26.3 (Tahoe).
…