Can I use system environment variables in favorite paths?
Yes. Tech support, sysadmin and other power users love it!
In any file path (folder, document or application), the system environment variables like %appdata%, %public%, %temp% or %userprofile% (etc.) are supported in favorite location (for example: "%appdata%\Microsoft\Templates" will take you to the folder "C:\Users\[username]\AppData\Roaming\Microsoft\Templates").
System variables can also be inserted in favorite advanced settings Parameters, Launch with this application and Start in. See What are favorites advanced settings?
You can also enter a location without path. In this case, the file is searched in the PATH environment variable directories or in app paths in the Windows registry. See Can I use relative paths in favorite settings?.