@Danp thanks for responding.

Your suggestions are very good, caused me to check other things and reveal some things:

My metadata and XOA config backups have started to fail with the error 'no such object' The metadata/config backup job's pool parameter was highlighted red with a warning symbol, showing a long GUID style id. I could not update the pool parameter - I have the spinning circle (of doom). After deleting the metadata/config backup job, I cannot recreate it - similar problem with pool parameter, none shown plus spinnng circle (of ongoing doom).

To cut a story shorter - I think I have fixed my problem by re-attaching the hosts/SRs to my XOA-community VM... Then I also noticed that the 'successful' backups are not successful as when I looked at their logs by clicking on the green 'successful' indicator in the backup logs I see they are skipping missing VMs. Terrific. So I have now updated all the jobs and reselected each VM, saved them and then re-run the backups.

So my big concern (understatement) is my XOA host VM backups have gone bad without any external changes, other than my applying XOA community updates. Do I need to check the backups carefully after every update? Surely not? Perhaps my method of updating, by running a script is horribly HORRIBLY flawed??

I found and have used an update script by Jarli01, applied as noted here. I've got a script to pull the latest update script and execute it. Not clear if I should inbclude the '-b stable' parameter.

#!/bin/bash sudo curl https://raw.githubusercontent.com/Jarli01/xenorchestra_updater/master/xo-update.sh | bash

To answer your useful questions:

Q. When did you last pull from the source?
A. Assume you mean 'when did I last retore from the backup volume'? Never. This is a first time for me.

Q. What type of SR(s) should be showing?
A. I have two: a local xcp-ng host (also hosting the XOA-community VM being used) and a remote xcp-ng host. Although it does seem an SR is an xcp-ng host, I am confused to the nomclature of 'SR' - I will try to find that out with Google ;). However, as mentioned above my hosts had disconnected themselves... WTF?

Q. Are you able to target an SR when defining a new backup job?
A. No! OMG. Also noticed the VMs have stopped being shown, no hostts connected!! WTF?

Q. Have I opened dev tools (F12), checked console for errors?
A. No, but I will when I next report something. Checking the backup page today I do get an error in index.js. I am happy to debug more and return trace/debug data if it is useful; below is what I see today on the backups page:

[React Intl] Error formatting time. RangeError: date value is not finite in DateTimeFormat.format() index.js:525 Z index.js:525 formatTime index.js:719 value index.js:1168 React 81 _renderOverlay Portal.js:84 componentDidMount Portal.js:47 m factory.js:665 React 12 notifyAll close closeAll perform perform perform S closeAll perform batchedUpdates batchedUpdates dispatchEvent

Q. Check system logs?
A. Assume you mean from xoa vm? I will include those next time I post - when I find where they are. Google will no doubt help me out there.