I have downloaded thief 1 and 2 played them fine without issue, went to play thief 3 and i can't pick any locks because my lock picks don't show. I have been told to download an unofficial patch but i had issues that the game wouldn't even start then any help is greatly appreciated :)

Vsynch needs to be ON in the options

you pretty much need this nowadays.

I have it on in the options i should have mentioned that sorry That's what i used but it crashed the game and wouldn't load, i only changed that holding shift runs and the turning was smoother

Its weird that the unofficial patch is not working, since it fixes everything!

I will assume you are on win10? Thats bound to cause compatibility issues

OK, got one last idea, in your Nvidia/AMD control panel, select the thief3.exe and cap the framerate to 60-90, then use a program like fraps e.g to check to see if its working

If you cant find the option on Nvidia/AMD panel or it doesn't work, download msi afterburner which includes rivatuner stats, with that program you can also limit the framerate

Keep in mind though that you always have to run rivatuner stats while playing the game.

Lots of games break this way if the framerate is too high, i am 100% certain this will work, if you run into any trouble, dont be ashamed to reply i will walk you through the entire process step by step

I'm having this problem as well, on Windows 10 also.

If the game doesn't work on Windows 10, why doesn't GoG detect this and warn me before downloading?

We shouldn't have to download additional third-party patches just to get the game to run...

Having said that.... I did download the "Sneaky Patch", and, so far, it appears to have fixed the problem.

I can't really tell for 100% sure, but from what I've read on various forums these past few months, it still seems to me like Windows 10 is an unfinished product, where updates may randomly break or restore compatibility with various older pieces of software and/or hardware.

So basically : there is no way to tell for sure if any such old game will or will not work on a machine running Windows 10, and even once you have tested it on your machine…
- that still may change with time and Windows 10 updates.
- some software that works on your machine might not work on another even with the same updates, and vice versa