Thanks for the reply. I’ve tried 3 different devices on 3 different ports. There is a yellow exclamation mark on the Renesas USB 3.0 Extensible Host Controller - 0.96 (Microsoft) - I have right-clicked to re-install the driver but it says it’s up to date.
If I double-click it, the device status says “Windows has stopped this device because it has reported problems. (Code 43)”. I’ve had a look on Microsoft for Code 43 and there is a section on the difference between Windows 8 and Windows 8.1 whish states “One of the reasons is that the device reports itself as supporting a USB version greater than 2.00, but does not provide the required BOS descriptor.”
I realised that all the USB/drives I’d tried were USB 3.0. I just tried using a USB 2,0 stick and that works, but only using a USB 2.0 port on the laptop; using a USB 3.0 port doesn’t work. And if I use a USB 2.0 multihub and plug a USB 3.0 stick into one of the 4 ports on it, that works, but only if I use a USB 2.0 port !
I used to wonder why you have both USB 2 & 3 ports on new laptops these days - now I know !
So it looks like it’s a problem with USB 3.0 - it would be interesting to know if other people have had this problem.
I’m considering either trying to disable the Renesas USB 3.0 Extensible Host Controller and re-install the driver or just roll back the update in case that causes further problems.