run applications from external hard drive
To open the app from an external disk, you have to refer to it explicitly using a Terminal command:

open /Volumes/&lt;volume_name_of_external_disk&gt;/&lt;path_to_application&gt;/Android\ Studio.app

Having never used Android Studio, I don't know if there is a space between 'Android' and 'Studio' in the app name. If there is, the back-slash character in the open command is required to delimit the space character.

Ex: open /Volumes/ExternalDisk/Applications/Android\ Studio.app