jspv07

The HDD power supply is one of those 12v/5v dual units with a combined plug.

Not worth buying a new one for over 20€.

I'll use the 2.5 HDD instead although it's smallish for my use.

Great thanks to WanWizard for the help.

Thanks for your replies narrowing down this problem to a power issue.

I have now replaced the 3.5 HDD with a 2.5 HDD connected to the powered USB on the receiver. T2 tuner is back and timeshift works.

I suppose the 3.5 HDD enclosure is faulty and draining too much power, or the 3.5 HDD standalone power supply is faulty.

Disk has been checked for inconsistencies.

HDD disk is in an enclosure. Power is supplied from an external power supply. The enclosure has a USB port for read/write.

This has operated perfectly for many years.

external HDD is a 3.5 disk connected by USB.

The problem was there with 8.3. I moved to 9.0 hoping it would go.