Hi all, my first post here. I have recently aquired a PowerMac G3 and am exploring a world of Apple I have never used before. I have a couple of questions. Is the 8.6 upgrade essential to be able to use the USB port for a thumb drive? I am currently on 8.5.1 and it says I need some drivers before it will recognise my 16GB stick.

I do believe you need 8.6 and the USB Mass Storage support (can still download directly from apple) https://support.apple.com/kb/DL1265?locale=en_US - For formatting the drive if you're sharing it between a modern PC/Mac I believe you'll need to format it as FAT - the only filesystem that they all can read/write to.

Easiest way would be to grab the 8.6 updater and that USB file and burn them to a CD, upgrade, then use the USB drive.

Brilliant, thanks. Will give it a go tonight.

So interesting issue, the 8.6 updater is not allowing an install due to being a U.K. machine but the updater is US or International. Is that a thing, a U.K. only updater?

You'll need the WW (world wide) updater https://macintoshgarden.org/apps/mac-os-85-851-update#Mac_OS_8.6 - MacOS86Upd_WW.ZIP

Wonderful, thanks Eric