Yes you can install Firefox to a different drive, but the 'bulk' of Firefox files will end up on the drive that has the operating system AppData folder. As browsing history and saved bookmarks builds up, the ratio will approach 10 to 1 or more.

My problem was that I missed the options-button on install.... Time will tell if it will be useful, for the build-up of data you mention in your reply. Thank you for your quick reply. Danielle

Possibly there are other workrounds. For instance you could install Firefox Portable that is a third party build and will install on an external hard disk drive or even a memory stick, and that drive or stick also stores the profile which is usually the part requiring a lot of space.

• Mozilla Firefox, Portable Edition your browser, your way... in your pocket™
• http://portableapps.com/support/firefox_portable#local_profile

On a modern Windows 10 computer I would not expect Firefox even with a large profile to be a big user of Disk space. Windows own built in graphical tools for looking at space use probably are not the best around. I usually study my Windows filesystem from another Operating System !

There are free Windows utilities that give a better indication of what the space hogs are. Some of those may take a while to run and collect data, but that is to be expected especially on a large hard drive, the benefit is that you see a better picture of how space is used and can often view and explore that data in much better ways than with Windows itself. See for example

• How-To Geek (slightly dated ) The 10 Best Free Tools to Analyze Hard Drive Space on Your Windows PC ->
  • https://windirstat.net/ -> https://www.fosshub.com/WinDirStat.html

N.B. It is possible to create and use a Firefox profile on an external hard disk drive, the problem is you will then really need the hard disk drive permanently connected, and the portable alternative may be both simpler and more flexible.

• Profile Manager - Create, remove or switch Firefox profiles
• http://kb.mozillazine.org/Profiles.ini_file
• http://kb.mozillazine.org/Moving_your_profile_folder#Using_the_Profile_Manager_to_move_your_profile

John99 said

Possibly there are other workrounds. For instance you could install Firefox Portable that is a third party build and will install on an external hard disk drive or even a memory stick, and that drive or stick also stores the profile which is usually the part requiring a lot of space.

• Mozilla Firefox, Portable Edition your browser, your way... in your pocket™
• http://portableapps.com/support/firefox_portable#local_profile

On a modern Windows 10 computer I would not expect Firefox even with a large profile to be a big user of Disk space. Windows own built in graphical tools for looking at space use probably are not the best around. I usually study my Windows filesystem from another Operating System ! There are free Windows utilities that give a better indication of what the space hogs are. Some of those may take a while to run and collect data, but that is to be expected especially on a large hard drive, the benefit is that you see a better picture of how space is used and can often view and explore that data in much better ways than with Windows itself. See for example

• How-To Geek (slightly dated ) The 10 Best Free Tools to Analyze Hard Drive Space on Your Windows PC ->
  • https://windirstat.net/ -> https://www.fosshub.com/WinDirStat.html

N.B. It is possible to create and use a Firefox profile on an external hard disk drive, the problem is you will then really need the hard disk drive permanently connected, and the portable alternative may be both simpler and more flexible.

• Profile Manager - Create, remove or switch Firefox profiles
• http://kb.mozillazine.org/Profiles.ini_file
• http://kb.mozillazine.org/Moving_your_profile_folder#Using_the_Profile_Manager_to_move_your_profile

On a small laptop with a 28 GB harddisk, I'm forever having trouble with diskspace. It's in our livingroom and we use it basically for Internetbrowsing and email. So now I am experimenting with the installation of large programs on an external harddrive, that is always attached. I have already followed your advice to install the portable version of FF and I will try it out. (as well as your other suggestions) Thank you very much for taking interest! Danielle