hdiutil: create failed - Operation timed out

Question

I am trying to create a Backup.dmg disk image in a folder on an SMB file system.

1. Using Disk Utility
2. Using hdiutil
   • hdiutil create -size 4t -fs APFS -volname backup Backup.dmg

Both operations start, but after a few minutes, they always fail with

create failed - Operation timed out

Fails the same way when trying to create an image on a USB-attached disk drive.

I recall doing this over a year ago on the same Windows box sharing SMB folders, with no problem.

<paranoia> Has Apple intentionally done something to prevent Macintosh users from running Time Machine backups on Windows file shares? </paranoia>

Chat GPT has many options but nothing useful. Google search shows other people with the same problem but not a lot of good solutions.

Answer 1

Yes, Apple has done something to make what used to work, not work anymore.

You cannot use an SMB drive with Time Machine unless the Samba server marks it as Time Machine... which is not an option in Windows...

Some people have suggested using Windows Subsystem for Linux, and running a Samba server there...

Thanks, Apple