Hello, 

I'm wondering if anyone can help.

I have a MacBook Pro on Tahoe 26 OS (Release Candidate).

Have just added a brand new, unencrypted exFat formatted Lacie 5TB HDD to the Archer AXE5400, which is on the latest firmware.

I can get all the way to the final step of setting it as the Time Machine backup location, but I get the below error message in Time Machine:

“BackupTM” can only be used if it contains existing Time Machine backups for this Mac.

The next major version of macOS will no longer support AFP network disks for Time Machine backups.

Separate to the point about it not working in the next macOS (27), it seems like it wants there to already be a Time Machine backup on the network drive, but as it is brand new, there isnt one. If i try to setup the drive with a time machine backup on it direct to the laptop, it will try to format the drive as APFS, which then means the router wont see it.

Anyone come across this error before or know how to fix?

Thanks