Starting in Safe Mode doesn't help

Do you have Firefox set to use automatic private browsing? You can check that on the Preferences page:

• Mac: "3-bar" menu button (or Firefox menu) > Preferences
• Linux: "3-bar" menu button (or Edit menu) > Preferences
• Windows: "3-bar" menu button (or Tools menu) > Options
• Any system: type or paste about:preferences into the address bar and press Enter/Return to load it

In the left column, click Privacy & Security, and then scroll down to the History section.

Either of these will invoke automatic private browsing:

• Firefox will: Never remember history
• Firefox will: Use custom settings for history + "Always use private browsing mode"

In that case, you may see old history from regular windows that is "read only."

Otherwise, you should be able to delete history unless there is a database problem which prevents updates.

To check on that, could you let us know what you get when you run the "Verify Integrity" function. That's here:

Open Firefox's Troubleshooting Information page using any of these methods:

• "3-bar" menu button > "?" Help > Troubleshooting Information
• (menu bar) Help > Troubleshooting Information
• type or paste about:support in the address bar and press Enter

Near the bottom, there is a section titled Places Database -- that's the file which stores history and bookmarks. Click the button labeled Verify Integrity. There may be a 10-15 second delay before results appear.

If all is well, the report that appears below the button should start with:

> Task: checkIntegrity
+ The places.sqlite database is sane
+ The favicons.sqlite database is sane

Does yours say that, or something else? You can select and copy the report, and then paste it into a reply for review and comment.

Places database does not check out. Response: > Task: checkIntegrity - Unable to check favicons.sqlite integrity: Error: Error(s) encountered during statement execution: database disk image is malformed > Task: invalidateCaches - The task queue was cleared by an error in another task. > Task: checkCoherence - The task queue was cleared by an error in another task. > Task: expire - The task queue was cleared by an error in another task. > Task: originFrecencyStats - The task queue was cleared by an error in another task. > Task: vacuum - The task queue was cleared by an error in another task. > Task: stats - The task queue was cleared by an error in another task. > Task: _refreshUI - The task queue was cleared by an error in another task.

Hmm, okay, the database that stores the zillions of site icons seems to have a problem:

> Task: checkIntegrity
- Unable to check favicons.sqlite integrity: Error: Error(s) encountered during statement execution: database disk image is malformed

So I suggest we rename that file so Firefox starts a new one. The downside is that you'll lose site icons for bookmarks and history, but I don't know any tricks for avoiding that. Here's the drill:

Open your current Firefox settings (AKA Firefox profile) folder using either

• "3-bar" menu button > "?" Help > Troubleshooting Information
• (menu bar) Help > Troubleshooting Information
• type or paste about:support in the address bar and press Enter/Return

In the first table on the page, on the Profile Folder row, click the "Show in Finder" button. If Finder highlights an icon with a semi-random name like a1b2c3d4.default, double-click it to display the contents of that profile folder.

Leaving the Finder window open, switch back to Firefox and Quit, either:

• "3-bar" menu button > Quit
• (menu bar) Firefox > Quit

Pause while Firefox finishes its cleanup, then rename favicons.sqlite to something like faviconsOLD.sqlite. (This is on the assumption that we might someday have a use for the current file, but if you have no interest in possibly using it in the future, you also could just delete it.)

Start Firefox back up again. Can Firefox access history again?

That mini-reset will hide the bookmarks toolbar. You can use one of these methods to show the toolbar list and re-enable the bar there if you like:

• (menu bar) View > Toolbars
• right-click (on Mac Ctrl+click) a blank spot on the tab bar (or the "+" button)
• in Customize mode > Toolbars button (see: Customize Firefox controls, buttons and toolbars)

To turn on the Bookmarks Toolbar, click it on the list.

Thanks, that worked. Is there a way to re-generate the icons?

sten2 Question owner said

Thanks, that worked. Is there a way to re-generate the icons?

Well, Firefox will add them back gradually as you browse. I don't know enough about the internals of the file to say whether some kind of import approach would be possible.

Many, many thanks Jeff, you are a legend.