Help moving Application Support files to external HDD

The problem is that applications want to put and look for stuff in ~/Library/Application Support/app-name folders so if you want to try the following as an experiment let us know how it goes:

cd "~/Library/Application Support/"

---make sure the OpenEmu application is not running before proceeding---

cp -pR OpenEmu "/Volumes/G-DRIVE mobile/Applications Support/OpenEmu"

mv OpenEmu xxx-OpenEmu

ln -s "/Volumes/G-DRIVE mobile/Applications Support/OpenEmu" OpenEmu

Note the consistent naming of "Application Support" as opposed to "Applications/Support Files" in your example to maintain consistent location strategy (not important but less confusing I think). I renamed OpenEmu to xxx-OpenEmu in case there is a problem so you can go back to the way it was if needed (just trash the new "/Volumes/G-DRIVE mobile/Applications Support/OpenEmu" folder if there was a problem as well as the soft link).

Another thing to think about is to simply relocate the entire /Users folder to another volume -- this would let you keep everything together as it was designed to be. Not sure if SIP would allow this or not. I used to do something like this on a Yosemite system, but that was before SIP. In any event you have to make sure the other volume is large enough to store the entire /Users folder before trying to copy it. And you would need to copy it in a special way that maintains permissions, attributes and ownership. And you would want to modify the /etc/fstab file to automatically mount the new volume in place of the /Users folder -- do a "man fstab" and "man vifs" to see how to do that (it has examples).

Is that what you had in mind? By the way is the "G-DRIVE" volume NTFS or HFS+ or ??? -- not sure if this will work if it's not HFS+

Good luck...

I thought it was something like that. If the program you are using offers no option to keep its files elsewhere, then it expects to find them in Application Support.

Is there a reason you don't want to simply drag one folder to another location using the Finder?

Drag and drop items on Mac - Apple Support

"To copy the item instead of moving it, press and hold the Option key while you drag and drop."

If you need to use Terminal use the mv command. Rather than type the lengthy pathnames just type mv followed by a space character. Then, drag the source folder into the Terminal window, then drag the destination's icon into the Terminal window, then press the Return or Enter key. The only keys you have to press are those for mv, space, and Enter. Terminal will provide the fully qualified pathnames.