I have an external hard drive with 3 partitions partitions a exFAT connected to a Windows 10 PC. I am able to mount and access the disks on my Mac wirelessly but cannot get TimeMachine to use this partition as a TimeMachine backup disk.
I am mounting it on my Mac using smb://XXX.XXX.XXX.XXX. I have also tried changing the unsafe disk property using the terminal command:
sudo defaults write com.apple.systempreferences TMShowUnsupportedNetworkVolumes 1
Anyone have any ideas how to get this to work?
Best Answer
Actually you are missing only one thing, TimeMachine will ONLY write to an HFS+ formatted disk so you need to backup to a sparseimage disk image file.
Create the sparseimage disk image with Disk Utility, be sure to select the image type as Sparse Image and the format as HFS+. Make it as big as the partition you are putting it on less a bit. The created disk image will only be a couple hundred MB.
If you are on Mojave even if you select HFS+ as the disk image it may be created as an APFS format. So you will need to mount the image, select it in Disk Utility and reformat it as HFS+.
Now you need to go into terminal and tell TimeMachine about the new backup volume that you have mounted from the SMB share:
Where "TimeMachineBackups" is the name of your mounted Time Machine disk image.
Now just set that volume to mount at startup under System Preferences > Users > Startup Items and you should be good to go.
I recently did this at work and it works great.