The Error Was Limited to One USB Destination
A user running ZimaOS 1.4.1-beta2 reported macOS Finder error 100093 while copying files over Samba. The same behavior occurred from two Macs. Browser-based uploads still worked, Time Machine backups completed, and Finder could copy files to the machine's other storage.
The important diagnostic detail was added later: Finder failed only when the destination was an attached USB drive. That distinction pointed away from a general network outage, bad Mac account, or completely broken Samba service.
The USB Drive Was Formatted as ExFAT
The user discovered that the affected USB disk used ExFAT after being moved among different homelab operating systems. They reformatted it as EXT4 and reported that Finder copying then worked normally.
This is a confirmed result for that specific system, not proof that every Finder error 100093 is caused by ExFAT. The thread contains no logs or controlled comparison explaining the underlying ExFAT interaction. Its useful lesson is the isolation method: compare destinations and check the filesystem of the one path that fails.
Why Browser Uploads and Time Machine Did Not Rule Out the Disk
Different file-transfer paths can exercise storage and sharing behavior differently. In this case, successful browser uploads proved that the user could write through the ZimaOS web interface, while successful Time Machine jobs showed that the backup path remained operational. Neither result established that ordinary Finder copies to the same ExFAT-backed share would succeed.
Because direct Finder copies to internal storage worked, the strongest differentiator was the USB drive and its filesystem rather than macOS as a whole.
A Safe Diagnostic Order
- Confirm whether the error affects every share or only one destination.
- Compare an internal disk with the attached USB disk.
- Record the filesystem used by the failing disk.
- Preserve or back up the data before considering any reformat.
- Treat reformatting as destructive and use it only when the data has been safely moved elsewhere.
The original user reformatted the USB drive, which erases its existing filesystem. The successful outcome does not remove the need to protect data before repeating that action.
Version Boundary
The report was made against ZimaOS 1.4.1-beta2 in May 2025. It should be read as a historical community case rather than a statement that current ZimaOS releases reproduce the same error.
FAQ
Does macOS Finder error 100093 always mean the network is broken?
No. In this case, the network and other transfer methods worked. The error followed one USB storage destination.
Did changing the USB filesystem solve this case?
Yes. The author changed the disk from ExFAT to EXT4 and confirmed that Finder copying worked afterward.
