Your Arcade Content Storage location can be changed manually to a user defined directory. You can *move the content to an external drive, or to a new location on your boot drive.
*Important: When you "move," your Content folder, you are simply telling Arcade to COPY the original folder to the designated file path. Arcade will COPY the Arcade Content folder in the new location, and update the database file responsible for telling Arcade where to find it. Never drag and drop an Arcade Content folder, as this will be cause for a full initialization and reinstallation of Arcade.
To do so, open the Settings page, click the Content Storage tab, and select Move To New Folder.
Select Browse, navigate to the desired location on your external drive, then click Apply.
You do not need to create a new folder in the new location, Arcade will create one for you called 'Arcade Content'. After copying your Arcade Content folder, you may delete your original content folder.
The original folder locations are as follows:
Mac: /Library/Application Support/Output/ARCADE/ARCADE Content
PC: C:\ProgramData\Output\Arcade\Arcade Content