Did you create the D:/Cache/Administrator/Firefox/ folder yourself?

Firefox doesn't create that folder itself. That folder has to be there in order for Firefox to use it.

Hi, yes, I created the folder first.

You're not using the leading and trailing quotation marks for that pref as you posted, are you??

"user_pref("browser.cache.disk.parent_directory","D:\\Cache\\Administrator\\Firefox\\");"

Also - C:\Users\Administrator\AppData\Roaming\Mozilla\Firefox\Profiles - did you put the user.js file there? Or in the actual Profile folder, where it belongs?

This extension - ChromEdit Plus - makes it a lot easier to work with user files from within Firefox - not need to "tour" the Windows file system looking for the correct folder to use.

Hi, without the leading/trailing quotes.

Looks like it might be a peculiarity of the Administrator account, I've just tried it on a standard user account and it works OK.

Thanks.

Sorry, that I wouldn't know about. My Windows Admin account is rarely used, and basically just used to set OS privileges for the other user accounts or for program updates / installation for the few programs that need Admin privileges for such. The last time I switched to the Admin user account and used Firefox, it updated 5 versions to the current version as soon as I opened Firefox - so it was like 6 months since Firefox was used there.

Did you try to delete the old cache folder to make sure that Firefox can't use it anymore?

Make sure that the user.js file is in the correct profile folder location and you should see the pref(s) on the about:config page on the next start of Firefox

(on about:config you need to use single backslashes and in user.js double backslashes)