Just started using GOG Galaxy tonight so that I could update AoM that was crashing me to desktop. Now I'm patched to 1.0.3.2 and whenever I use the SHIFT key to stay in place and shoot I seem to get rooted in place and stand and fire continuously. Sometime pressing the SHIFT key again frees me, but not always. And it just got me killed. I have no mods. Was working fine before I patched. I "did" have an issue installing the most recent version and had to use repair to get it finished. Any ideas on how to procede at this point? Does anyone know if I can uninstall and reinstall without losing my game progress?

Grim Dawn's savegames are located under C:\Users\Documents\my games\Grim Dawn. Uninstalling should normally ask whether you want to delete the save files as well, but when in doubt, you can simply back them up to be on the safe side.

Can't help you with the shift issue, but from my experience, Grim Dawn tends to produce astonishing errors if the installation is flaky, so a clean reinstall might be your best bet.

EDIT:
I *THINK* I found what might be causing your issues...

From the official Grim Dawn Forums:
It's the new casting mechanics, it makes everything that is not melee range to be cast from place instead of making you move within range... The only way around it is to go into Options Menu > General and select Classic Casting to go back to the old casting method.

This sounds quite a bit like what you are describing.

Another possible issue - "sticky keys" in windows.
Shift can cause it if you hold it for 8 sec or press 5 times fast.