TimeMachine does't allow Volume Selection

[aguenther]

I have set up my old MBP as Nas. The Time Machine Volume also appears on the desktop of the new MBP. However, I cannot select any other volume in the Timemachine system settings than the default >>Airport Extrem Capsule<< The Airport Utility does not display other WiFi devices even though the old MBP is logged into the same network and its volumes are also displayed on the desktop of the new MBP.
Can anyone help me?

 

[mode11]

I'm having essentially the same issue. Until a couple of months ago, I was backing up an iMac (El Cap) and MBA (Mojave) to a shared Time Machine folder on a disk in a Mac Pro (Mojave). Now neither client can see the network disk in Time Machine preferences, despite being able to mount the same disk in Finder.

The Mac Pro volume being shared was HFS+ (journaled, encrypted). Whilst troubleshooting, I saw an Apple support note that said Mojave could only share Time Machine folders from APFS disks. So I formatted the volume as APFS (encrypted) and copied the Shared folder back to it. The iMac client still can't see the shared disk in TM prefs. Haven't had a chance to try with the MBA yet, but that will be my next step.

 

[aguenther]

Thank you for the information. I am curious how you will succeed.

 

[Honza1]

I think someone reported here few days ago, that older OSX systems cannot use for TM shared disks exported from Mojave. Something about Mojave security requirements which prevents this from happening. This was after discussions with Apple support - and will not be fixed. I use for TM disks from El Cap on Mojave. I cannot use for TM disk exported from Mojave to El Cap.

 

[aguenther]

I think someone reported here few days ago, that older OSX systems cannot see/mount shared disks exported from Mojave. Something about Mojave security requirements which prevents this from happening. This was after discussions with Apple support - and will not be fixed. I have tested that one can share disks from older OSX to Mojave (and older OSX). But my understanding is, that one cannot share disks from Mojave to older OSX versions.

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Hi, l am afraid, you might be right.
I haven’t got any other information so far.
Regards

 

[mode11]

Interesting. Haven’t had a chance to test with the MBA on Mojave yet, as was busy all weekend. Hopefully tonight.

Would update the iMac to Mojave (it keeps asking), but not sure if it will break WiFi? It’s an early 2008 24”, but does have a 3GHz C2D, 8800GS and a 500GB SSD.

 

[mode11]

Just tested. The MBA (on Mojave) is backing up to the Mac Pro (also Mojave) just fine.

Despite the regular pop-up invites to update to Mojave, the iMac won't actually do so when attempted via the App Store. On investigation, El Cap is the end of the line. Dosdude's patcher is an option, but I don't particularly feel like having a hacked system that will need maintaining (it's someone else's primary machine).

Is there any other workaround for TM on El Cap over a network, to a Mac running Mojave? Can't it just mount a remote disk (even on a Mojave system) and write to a sparsebundle? If TM won't play ball, I may just use SuperDuper to make regular incremental backups over the network.

 

[mode11]

Just to update anyone who’s having the same issue, I got it working. Incidentally, I had to resolve an issue with my router first, which had switched gateway from 10.0.0.1 to 192.168.0.1, causing some reserved IPs to break.

Anyhow, when using older versions of macOS, you have to connect to the Mojave folder sharing the TM images using AFP. Note AFP only works on HFS+ disks, not those formatted as APFS.

I had converted to APFS after reading an Apple support note that only this format is supported for shared TM discs in Mojave, though this isn’t actually the case. I can’t find that note online any more, and in any case both my Mojave and El Cap clients are backing up fine over the network to an HFS+ disk, over SMB and AFP respectively.