Firefox 11+ versions have support via browser.download.lastDir.savePerSite pref to disable to disable the feature to remember the download directory based upon the URL.

The browser.download.lastDir.savePerSite pref doesn't exist by default (it is hidden).
Create a new Boolean pref with the name browser.download.lastDir.savePerSite and set the value to false.

• http://kb.mozillazine.org/about:config

See:

• [/questions/887248?page=2#answer-318910]
• resource:///modules/DownloadLastDir.jsm

(EDIT: changed browser.download.lastdir.savePerSite to browser.download.lastDir.savePerSite)

I tried that, but it didn't work. I suspect that and already existing string titled browser.download.lastDir is interfering with it (see attached screenshot)

I tried right clicking on it, selecting Reset and restarting Firefox. I tried right clicking, selecting Modify, typing in false and restarting Firefox. Neither action got any results. There doesn't appear to be any way to delete it as http://kb.mozillazine.org/About:config only says that added preferences can be removed.

What should I do now?

You may need to clear the Site Preferences to remove already stored data.

• https://support.mozilla.org/kb/Clear+Recent+History

I tried that with no tabs open except for a blank New Tab. In the dropdown, I selected Everything and in the checkboxes, I selected Browsing & Download History, Form & Search History, Cookies and Cache. That had no effect.

Is there anything else I can try?

Also, is there any chance that FireFox's developers will add disabling per-site remembering of download directories as an option in Options instead of it being a hidden feature? Considering how many users dislike per-site remembering, I think that's what they should do.

You need to remove the "Site Preferences" as I wrote above because that is where the download folder may have been saved if you have saved an image from an URL.

(for the record)
Posted today by Cloudchaser in another thread, /questions/923329

I was advised to try posting to the bug report area. That found a solution. I was told

I'm 99% sure the problem is that you created the preference

browser.download.lastdir.savePerSite,

as opposed to

browser.download.lastDir.savePerSite

(lowercase "d" instead of capital "D" in lastDir)

So I recreated the preference with the capital D and that disable per-site remembering of the download directory