Hi I have witcher 3 installed but i wish to move it to my SSD. I also have some mods installed with vortex. What is the best way to do this without having to unistall and redownload the game? Can I simply copy the whole witcher 3 folder and just cut and paste it on the SSD drive? not sure about this. thanks

If you're using Galaxy:

1. Move the game to the other drive/folder.
2. "Scan & Import" that drive/folder in Galaxy
3. "Verify & Repair" the installation (fixes registry entries etc.)

Beware that if you have mods that overwrite game files, those will be restored to their original version, so keep backups. Extra files from mods will be left untouched afaik.

Tom's advice is probably the best option for any GOG game as Galaxy is pretty good with rescanning already installed games if you point it at them.

Another way however which should work with any game or software in a way that is agnostic to the software if there doesn't happen to be a fairly easy approach as the above suggestion, is to exit any software that may be accessing file's in the game/program's directory, move the directory to another drive as desired, and then set up a Windows junction point in the original location which points to the new location.

For those unfamiliar with the junction point feature, it is a lower level administrative feature on Windows designed for just this purpose, usually used by experienced system administrators and other gearheads. A junction point is like a shortcut in a way, where it exists in one place but points to something located somewhere else, but while a shortcut is a higher level operating system concept, junction points are a low level feature of the filesystem and transparent to all software. In short, junction points are a neat way of tricking programs into thinking files are on one drive/directory when they're actually somewhere else.

Windows unfortunately does not come with GUI tools to set up junction points or other low level filesystem concepts (like hard links or symlinks), so one has to use commandline tools to do it, or install 3rd party software. I use a free addon called "Link Shell Extension" for Windows which adds a right click menu to File Explorer to set the source for a junction point/symlink/hard link/ etc. and then lets you drop one of those in the folder of choice to establish the given link. Junction points are very useful for this, as well as for hand picking various subdirectories on an SSD drive that don't really benefit from being there, relocating them to a hard disk instead, and pointing the original location to the hard disk with a junction point to save space on the SSD.

I wouldn't use a junction point for a GOG game as the suggested solution is quicker and easier and more proper, but junction points are very useful to know about for cases where there is no other option, or where it might require uninstalling and reinstalling something or other inconveniences.

I figured I'd mention it here for future reference for anyone that might benefit from the info.

https://schinagl.priv.at/nt/hardlinkshellext/linkshellextension.html

I will post this, even though I will be downvoted for it. It is always best to install any program directly from the installers. Most mods will tell you to install a fresh base copy and then mod from there. Whilst it is possible to “portability” certain software, a lot requires ref links, third party software, and other such things in place.
As such I would always, and most strongly (as it’s the only real reason to buy from here) to download and store the offline installers, even if you don’t use them, they will then always be present for a new reinstall. Do note that for some games it’s worth having multiple installs of a game - elder scrolls/fallout for instance, so using a game manager like galaxy is not advised.
Now I haven’t used vortex (and don’t use galaxy), but I have used other mod managers and you need to be careful that moving it will not break anything, I.e. could it rely on mods stored elsewhere.

i did this but without verifying and repairing. I also added an extra first step of uninstalling the mods in vortex then I reinstalled them afterwords..it seems to of worked. I am a bit confused about vortex though since the game directory was changed but i did not change anything in vortex. other then just reinstall the mods in its current profile . does it just automaticly find the game or something regardless of if you move it?