I don't have a lot of room on my C: drive, a 120 GByte SSD because of all the crap I have on this computer. My C: drive keeps warning me of dwindling space.
As such I want to install Arduino on another drive, along with all the libraries. It doesn't matter if my sketches go to the C: drive (in User/documents...) because they are quite small don't take much space.
I already HAVE the IDE installed on my D: drive where I have tons of space, but the program looks to User/documents for libraries. I looked at the preferences file and there is no facility for changing the library location as much as I can figure.
How do I do this? I have libraries from previous iterations of Arduino use a few years ago that I might want to use again because some are vendor specific.
The libraries folder location is relative to the sketchbook folder. You can set the sketchbook folder location via File > Preferences > Sketchbook location.
Good tip about the portable installation. If you install boards via Boards Manager that can use a lot of space on C:\ but if you have your IDE installation on D:\ and running in portable mode and have the sketchbook on D:\ then the IDE should have a minimal usage of C:.
I have gotten by with 80 GB magnetic system drives on my Windows computers for the last decade. It did force me to keep things tidy but is kind of annoying at times. I just upgraded to 240 GB SSDs last week and it feels quite luxurious.