Time machine issues on Catalina

[Wder]

I have an issue with time machine, which I hope someone can help with. I have an old MacBook Air running El Capitan, and on that machine time machine is running without issues on my Synology. I recently got a MacBook Pro on which I am running Catalina. I managed to got time machine to work on it, but every time there is an update I have an issue where I get a message that the volume for time machine on my Synology is not available. I can acces the volume in finder without issues however. Manually deleting the old backup copy and then restarting time machine seems to work out fine, but of course I do loose my older backups every time this way. Any suggestions ? Thanks a lot in advance ! I am not a pro in networking IT issues, so I hope the solution won't be too difficult, I have the impression I can find some clues on Synology forums, but they are so technical I hardly understand ...

 

[Rodan52]

A bit of clarification here. Are you saying that you are backing up both of your devices to one Synology? I assume this is a NAS device?

 

[Wder]

Indeed. 1 Synology NAS in the network, and I run TM from both laptops to that NAS

 

[Wder]

Anybody having comparable issues ?

 

[HDFan]

but every time there is an update I have an issue where I get a message that the volume for time machine on my Synology is not available. I can acces the volume in finder without issues however. Manually deleting the old backup copy and then restarting time machine seems to work out fine, but of course I do loose my older backups every time this way. Any suggestions ?

What happens if you remove the Synology TM Share disk in Time Machine Preferences and add it back again?

 

[Wder]

Then it works for a while, but a couple of days later it gives errors again... Strangely enough, the TM seems to work fine on an old time capsule, but not on the Synology...

 

[HDFan]

Then it works for a while

It sees the older backups? You don't have to start from scratch?

 

[Wder]

I always get an error that it cannot complete the backup to Synology, so I have to remove the entire file and start from scratch again. Then it works fine again for a couple of days, after which the same problem arises again. Strangely enough, no issues with TM on the Synology from the old air, and no issues with the MBP to the time capsule. Only combination Synology - MBP gives issues...

 

[HDFan]

I'm wondering whether the issue is network related, or an issue with the TM software or hardware at either end. Running TM to my QNAP NAS I also got the message that the TM backup was corrupt and needed to be restarted from scratch. I was also running other Carbon Copy Cloner tasks at the same time and they were failing because they could not find the network share. I was working with QNAP support about network share issues at the time. Eventually it stabilized and now both CCC and TM tasks are running without errors.

Do you have a local attached disk that you can use for TM? If you get issues there that might tell us something.