Sounds like the Raspbian Lxpanel memory leak. It is/was in Raspbian Stretch and I don't think anybody bothered to fix it without upgrading to Raspbian Buster. Runs fine for ever until you try to do anything remote that uses the graphical interface, then after a while it starts to squeak "Failed to fork (Cannot allocate memory)" and nothing works, even a console. Daft workaround is to login with VNC or whatever and turn the bluetooth on and off.

Crikey. checked my notes, the server was assembled from parts in mid-2012(!)

Ran headless for 6 years then stuck a GT520 (purchased with the rest in 2012) in it when it became my main dev platform.

The production server role was a demented skunkworks experiment that worked rather too well, and the rest is history.

I suppose it could be a hw issue ...

I thought the Nouveau driver used to have issues but those had been ironed out now? At least that's the impression I've gathered from occasionally scanning through threads with people asking for help - that most people don't need the proprietary Nvidia drivers any more.

Why've you got a GUI on a production server anyway?

Not a fan of Gnome either, but it's simple enough for non-power users. Cinnamon is adequate, but also limited in places, and the widget code is ugly and confusing. I was planning to switch from Cinnamon to Plasma (since I was ok with that in Debian 10), but the latest version of Plasma seems both slower and buggier, and it just doesn't gel with me, so now I'm faced with tedium of downloading half a dozen different distros/DEs to see if I can get on with any of the others.

Well it's one of those weird things where the pandemic and WFH reared its ugly head, so it got pressed into full-time service in that role, which it does great.

I'll have to consider another arrangement soonish, since arguably it should be on its last legs, I have to refresh the Ubuntu LTS it's running anyway and yada. Hopefully I can keep using it for a dev box, if I can sort out the gui issue, maybe try a different legacy gpu for that.

I've tried quite a few different de's and settled on xfce for being lightweight and stable, with no stupid wannabe OSX/Windows eye candy BS.

Nice to see this one resolved.

But really, why aren't your sister's workplace providing a computer?

*shrug*

If I could share more details, everyone would be asking why they're not requiring the use of machines they've provided, pre-configured and suitably locked-down, but why be competent when you can be cheap?

Hope they're all stocked up on BTC.

Worse than not just providing staff with correct tools then. Worrying.