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Firefox 15.0 is storing cache even in PBM, please help me!

  • 20 replies
  • 5 have this problem
  • 853 views
  • Last reply by argonvegell

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I have started a thread yesterday on this issue on Mozillazine, and I have followed their directions and none seem to solve my problem.

I have downgraded back to Firefox 14.0.1, and these problems do not appear on this version, how do I fix this problem on Firefox 15.0?

Link to thread on Mozillazine: http://forums.mozillazine.org/viewtopic.php?f=38&t=2528849

Chosen solution

FYI: Firefox 15.0.1 has been released, so you can update.

Read this answer in context 👍 0

All Replies (20)

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Does Firefox still use the cache if you use Clear Recent History to clear the cache when you close Firefox?

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I'm not sure what you mean, but here's what happens, first I clear both Cached Web History and Offline Web Content and User Data to 0, then I set Firefox to Never Remember History, then I clear all it's History, press Okay and exit, then I reload, I check on Cached Web History, it has a number of bytes on disk, and Offline Web Content and User Data remains 0.

But in Firefox 14.0.1, both Cached Web History and Offline Web Content and User Data are blank.

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Where do you check that "Cached Web History" ?

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Options > Advanced > Network > Cached Web History and Offline Web Content and User Data are on there.

Right now, since I'm using PBM on Firefox 14.0.1, they are blank, but on Firefox 15.0, Cached Web History, for example, says, "Your web content cache is currently 180KB of disk space", while Offline Web Content and User Data says, "Your application cache is currently using 0 bytes of disk space".

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Switching to PB mode doesn't clear the current cache, but merely disables it until you exit PB mode.

OK, I checked it and Firefox 15 doesn't show on the about:cache page that the disk cache is disabled or not being used when you switch to PB mode like Firefox 14 and earlier versions do that hide that section when you enter PB mode.

  • Tools > Options > Privacy, choose the setting Firefox will: Use custom settings for history
  • (de)select: [ ] "Always use private browsing mode"
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That's the same directions I followed on Mozillazine, it didn't work, is it possible my installer is corrupted, how would I confirm this, I downloaded from: http://www.mozilla.org/en-US/firefox/new/

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Wait a minute, what did you mean, (de)select "Always use private browsing mode"? I should deselect it on the custom settings?

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If you select it then you enter PB mode as you can see by inspecting the cookies (you need to close and reopen the options window on Windows) after flipping that box.
If you deselect it then you leave PB mode.

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Okay, I entered PBM, cleared history, then clear both caches, exit and reload Firefox, checked on both caches, for example, Cached Web History says, "Your web content cache is currently 3.0KB of disk space", and I did a Google search, the web content cache increases, I even double checked if I'm using PBM.

I'm confused, what is the matter with my Firefox.

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Copy and paste this code in the Code field in the Error Console and click the Evaluate button.

  • Firefox/Tools > Web Development > Error Console

var pbs = Components.classes["@mozilla.org/privatebrowsing;1"].getService(Components.interfaces.nsIPrivateBrowsingService);
void(alert('Private Browsing is '+((pbs.privateBrowsingEnabled)?'on':'off')));

Modified by cor-el

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Is this a new feature of Firefox? I read on the changelog, they are optimizing the memory use of add-ons, is that the reason why the web content cache is not disabled in PBM? Is this normal what I'm experiencing?

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Okay, I will do that, thanks

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In PB mode nothing is stored on disk and that includes disabling the disk cache and only use the memory caches (including the image cache).

If the memory cache isn't working then check the related browser.cache.* prefs on the about:config page.

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It said private browsing is on, but the cache is still increasing after I do Google search, it says, I'm using 202KB of disk space.

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This is what I am getting from about:cache

Information about the Cache Service Memory cache device Number of entries: 77 Maximum storage size: 18432 KiB Storage in use: 529 KiB Inactive storage: 529 KiB List Cache Entries

Disk cache device Number of entries: 22 Maximum storage size: 880640 KiB Storage in use: 202 KiB

List Cache Entries Offline cache device Number of entries: 0 Maximum storage size: 512000 KiB Storage in use: 0 KiB

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How can I report this as a bug in Bugzilla?

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There's already a bug reported, Bug 787743

(Disk cache entries from Private Browsing mode are not cleared after returning to normal browsing mode, in Firefox 15.0 and above)

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For anyone affected by this issue, Firefox 15.0.1 will be released sometime this week to correct the private browsing issue.

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Chosen Solution

FYI: Firefox 15.0.1 has been released, so you can update.

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Thanks cor-el, I upgraded and it works, great job Mozilla Team!