I am not sure if this solution still works, but this post from a few years ago did the following:

Go to Options->Advanced->Network. Check Override automatic cache management. 2. In about:config, highlight 'browser. cache. check_doc_frequency.' Right click then choose Modify. Enter value '0' or value '2.'

That didn't solve the problem.

Can you check your about:cache?storage=memory&context=

Mine tells me "Storage disk location: none, only stored in memory ", and if yours does as well I think it makes sense that it would clear after closing.

In the about:config page there is an entry for browser.cache.memory.enable, now I am not 100% sure, but since you are testing on a new profile anyways, you can try setting that to false and hopefully it stores the cache on your local storage where it can be saved even if Firefox closes. I can't guarentee that it will work though since I haven't tried keeping my cache between sessions.

You can see the following link for more details that might help you in the about:config entries: https://developer.mozilla.org/en-US/docs/Mozilla/Preferences/Mozilla_networking_preferences?redirectlocale=en-US&redirectslug=Mozilla_Networking_Preferences

If you find a different solution that works, please share!

That would normally only happen when Firefox didn't close properly and find the dirty cache flag set on the next start. If that is the case then you should see a cache.trash folder that has the content of the cache of the previous session.

Firefox can't clear the disk cache when you close Firefox because the disk cache is disabled when you use "Clear history when Firefox closes" to clear the cache and the disk cache section is missing on the about:cache page.

Disabling memory cache didn't help.yes i do see many cache.trash folders every time after I close Firefox.I checked on Task Maanger and every process associated with FF and plugins were shut down.

I went to C:\Users\USERNAME\AppData\Local\Mozilla\Firefox\Profiles\myprofile

There is a file names _CACHE_CLEAN_ and it contains only one character - "1".I changed it to "0" Closed Firefox.It created a new folder in my profile directory called "Cache.Trash29055" and the _CACHE_CLEAN_ file(which is located in the profile root directory) automatically changed to "1" for some reason.I changed it back to 0 and made the file "read-only".The 0 stayed 0 but cache wasn't saved.Then I removed the read-only attribute and next time it turned 1 again.Maybe messing with this file changed something but before I used to have "Storage disk location: none, only stored in memory " but now it actually gives me a directory where the cache is saved and it's in "blahblah\Myprofile\cache2" folder.

Here is the best part.The cache does not appear in about:cache area right away but when I wait 45 seconds it reappears automatically.We're talking about few hundreds kilos, not much data so it's not like FF needs a minute to load tons of data from my SSD.Maybe something is wrong that it takes such a long time for cache to load. I don't keep FF open all the time so when I open it I go to my regular sites right away so right now even though the cache works, I can't take advantage of it unless I open FF, wait 45 seconds, then start browsing.

15 minutes later: I just went away from computer for 15 minutes.Came back and tested it again but this time the cache appears right away.No need to wait 45 seconds.I don't understand why but it appears to be functional now. My default profile works too after I did the same thing.I think something is wrong with Firefox remembering settings because when I go to Options>Settings>Advanced and I check all the boxes like Health Report,Telemetry and Crash Reporter, after I restart the browser only Telemetry box is remained checked.I should probably reinstall the browser.

I used Revo Uninstaller to totally wipe everything.Restarted PC.Installed the latest Firefox from official website. Visited random websites.Disk Cache became 3MB. Closed Firefox.Waited 15 second.Opened Firefox.A new folder named "cache.Trash10300" was created RIGHT AFTER I opened the FF.At this moment the About:Cache shows 0MB cache. 25 seconds later the cache.Trash.10300 folder disappeared.About 20 seconds after that the about:cache showed the 3MB cache. Storage disk location: C:\Users\USERNAME\AppData\Local\Mozilla\Firefox\Profiles\kpath8x5.default\cache2 All this time the _CACHE_CLEAN_ has the value of "1".I have not changed it at all.

I did the same thing multiple times.Closed FF,relaunched and checked the cache page, after doing it few times the cache appears instantly now.This time the new cache trash folder was not removed by itself and now I get a new trash folder every time I open FF! I get about 5-6 trash folders then they all disappear the about:cache still shows the cache instantly.

Now just I closed FF.I don't have any trash cache folders.Opened FF.A folder named Cache.Trash18308 was created.About:Cache displayed cache instantly.Closed FF.Opened it again and there is another cache trash.Now I have two trashes and about:config still shows cache instantly. I'm trying to find out why sometimes it takes a minute for cache to show up in about:cache.

Rebooted the computer. I have a Cache.Trash18308 folder. Launched FF. A folder named Cache.Trash19973 was created while an existing folder named "cache" was deleted.10 seconds later Cache.Trash19973 was deleted.The about:config showed cache instantly.

Things seem t work fine now. Other settings like Telemetry,Health Report e.t.c now they stay checked so the settings are saved properly after I close FF. Occasionally when I launch FF I'll get a message that FF is still running.It appears that it doesn't always close properly.This has been happening with Firefox with many years.During the testing,I always made sure that FF was closed including all of its plugin processes.

5 hours later: Cache works fine.Always shows instantly in about:cache page.

Note that the current release use a new cache service named cache2.

• https://www.mozilla.org/en-US/firefox/32.0.1/releasenotes/
• http://www.janbambas.cz/new-firefox-http-cache-enabled/