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Firefox 20.0 Private Browsing Holds on to Logins

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Previous to Firefox 20.0, you would click "Start Private Browsing" (I can't remember the exact wording) and for example, login to Site X. When you were finished, you would click "Stop Private Browsing." Later in the day, you would click "Start Private Browsing" and go to Site X. Site X would not show you logged-in.

That's no longer the case.

In Firefox 20.0, you click "New Private Window" and login to Site X. When you're finished, you click on Close (the x). Later in the day, you click "New Private Window" and go to Site X. Site X still shows you logged-in from the previous private session.

So "Private Browsing" is not actually private.

The only way to ensure that this doesn't happen if you go to File > Exit but that shuts down everything including non-private browsing.

Previous to Firefox 20.0, you would click "Start Private Browsing" (I can't remember the exact wording) and for example, login to Site X. When you were finished, you would click "Stop Private Browsing." Later in the day, you would click "Start Private Browsing" and go to Site X. Site X would not show you logged-in. That's no longer the case. In Firefox 20.0, you click "New Private Window" and login to Site X. When you're finished, you click on Close (the x). Later in the day, you click "New Private Window" and go to Site X. Site X still shows you logged-in from the previous private session. So "Private Browsing" is not actually private. The only way to ensure that this doesn't happen if you go to File > Exit but that shuts down everything including non-private browsing.

Modified by Yael K. Miller

Chosen solution

I have just managed to solve this problem but I have no idea why it solved it.

  • Disabled all my add-ons
  • Enabled them one-by-one (testing the issue)

All's well for now. Even with Norton Toolbar enabled which I thought might have been an issue.

Here's hoping it stays fixed.

Read this answer in context 👍 9

All Replies (6)

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I just tried this:

  • New Private Window
  • gmail.com - redirects to login page
  • login to Google account
  • search inbox
  • close window (using the "red X")
  • New Private Window
  • gmail.com - redirects to login page
  • No history from previous session on the History menu

This was with my default cookie permission setting for all *.google.com of Allow for Session. In other words, I do not keep Google cookies across sessions; they expire when the browser closes.

I went into about:permissions and changed my cookie permission for all *.google.com domains to Allow. I repeated the test and got the same result.

So I'm not sure why yours persisted information across your sessions. Do you use any session management add-ons that might play a role?

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What do you mean by "session management" add-ons?

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What do you mean by "session management" add-ons?

For example, there is an extension named Session Manager that stores information about your Firefox session separately from Firefox's own session restore file.

There also are add-ons that keep track of data entry on forms for purposes of crash recovery, such as Lazarus.

Since the concept of individual windows being private or non-private is new in Firefox 20, any add-on that stores browser data and hasn't been updated to distinguish between the windows might accidentally keep some private data.

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No, I don't use session management add-ons.

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Chosen Solution

I have just managed to solve this problem but I have no idea why it solved it.

  • Disabled all my add-ons
  • Enabled them one-by-one (testing the issue)

All's well for now. Even with Norton Toolbar enabled which I thought might have been an issue.

Here's hoping it stays fixed.

Modified by Yael K. Miller

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Air bubbles, stray electrons... sometimes there is no explanation!