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Does clearing cache in Preferences clear all caches?

user1251572
user1251572
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I assume it is likely, but I just want to check, when I clear the cache as instructed here (https://support.mozilla.org/en-US/kb/how-clear-firefox-cache) with the "Clear Now" button, does this empty all caches? So including the memory cache (which would normally be cleared on the closing of Firefox) and not just the persistent one stored on disk? I have Firefox 47 installed.

I ask this because sometimes I go somewhere where I suspect there is a malicious image either with a script or exploiting some vulnerability and I would just like to know if there is an easy way without having to restart Firefox to become 'safe' (as much as I can be) again. If this button does clear all caches and I use it after seeing a malicious image, will it suffice or should I still restart Firefox?

I assume it is likely, but I just want to check, when I clear the cache as instructed here (https://support.mozilla.org/en-US/kb/how-clear-firefox-cache) with the "Clear Now" button, does this empty all caches? So including the memory cache (which would normally be cleared on the closing of Firefox) and not just the persistent one stored on disk? I have Firefox 47 installed. I ask this because sometimes I go somewhere where I suspect there is a malicious image either with a script or exploiting some vulnerability and I would just like to know if there is an easy way without having to restart Firefox to become 'safe' (as much as I can be) again. If this button does clear all caches and I use it after seeing a malicious image, will it suffice or should I still restart Firefox?

Chosen solution

Yes. Clicking the Clear Now button should clear all cache though this can take unknown time because this is done in the background in another processor thread. You may have to reload the page a few times to check the progress.

You can see the current cache use on the about:cache page.

Read this answer in context 👍 5

All Replies (2)

cor-el
cor-el
  • Moderator
  • Top 10 Contributor
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Suluhisho teule

Yes. Clicking the Clear Now button should clear all cache though this can take unknown time because this is done in the background in another processor thread. You may have to reload the page a few times to check the progress.

You can see the current cache use on the about:cache page.

Foxy Der Fox
Foxy Der Fox
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I checked the cache info using about:cache and this cache2 is not EVER cleared no mater how many times I click the Clear Now button and/or refresh and click again nor how long I wait for it to clear:

Number of entries: 12 Maximum storage size: 358400 KiB Storage in use: 196 KiB Storage disk location: C:\Users\Ron\AppData\Local\Mozilla\Firefox\Profiles\5gv0c9f5.default\cache2

196 KB is exactly the amount that does not clear. I can delete cache2 and the problem is gone until cache2 is rebuilt and entries are entered.

Any way this can be stopped from rebuilding cache2 and/or have the Clear Now button actually clears ALL caches?

Update: If I check the box for In Browser Element on the about:cache page, click Update button, I get:

Number of entries: 0 Maximum storage size: 358400 KiB Storage in use: 0 KiB Storage disk location: C:\Users\Ron\AppData\Local\Mozilla\Firefox\Profiles\5gv0c9f5.default\cache2

I can go back to Options/Advanced/Network again, refresh as many times as I want, click Clear Now button and it still resets to 196 KB! Is cache2 tied to other option settings like those options under Security and/or Privacy?

Modified by Foxy Der Fox