hi, with the offline installers from https://www.mozilla.org/firefox/developer/all/ you're able to set a custom install path.

Regardless of where you install Firefox, the "bulk" of Firefox files will end up on the same drive as the Windows operating system; the C:/ drive.

Firefox creates the profile folder in a hidden location in "AppData\Roaming" (main profile) and "AppData\Local" (temp data like disk cache). The files in the profile folder also take a l;arge amount of space like posted above.

You can create a new profile on another drive with the Profile Manager. You first need to create a separate folder that doesn't have any other files to be used exclusively as the profile folder before starting the Profile Manager. You can use the Choose Folder button to point to this profile.

Note that you should never use "Choose Folder" to point to a folder that already contains other files.

• https://support.mozilla.org/en-US/kb/profile-manager-create-and-remove-firefox-profiles