Before moving your Steam game, you’ll need to use Steam to create new save locations for your games. First, open Steam, then in the top-left corner click “Steam -> Settings.”
In the Settings window, click Downloads in the pane on the left, then “Steam Library Folders.”
In the Steam Library Folders window, click “Add Library Folder,” then select the location on another drive where you’d like to install Steam games. Note that this doesn’t replace your original installation location for games but gives you an additional location to install them. Also, you’re only allowed to install Steam games in one location per drive.
Once you’re done, you can add additional Steam Library Folders to other drives in the same way. To change the default Library Folder, just right-click the one you want in the list and click “Make Default Folder.” From now on, each time you install a game Steam will ask you which of your Steam Library Folders you’d like to install it to. Now, to move an existing game to another drive, go to your Steam Library, right-click the installed game and click Properties. In the Properties window click the “Local Files” tab, “Move Install Folder,” select which of your Steam Library Folders you’d like to move the game to and click “Move Folder.”
Conclusion
The process may take a couple of minutes, but once it’s done, the game will be completely ported over to the new drive. We’ve never had issues using this feature, so you can move games around fairly freely without worrying about anything going wrong. Cheers, Valve.