Make sure you are not blocking content.

Start Firefox in Safe Mode {web link} by holding down the <Shift> (Mac=Options) key, and then starting Firefox.

A small dialog should appear. Click Start In Safe Mode (not Refresh). Is the problem still there?

One issue that seems more common lately is Firefox's Tracking Protection feature. When it is blocking content in a page, a shield icon will appear at the left end of the address bar next to the padlock icon. This article has more info on managing this feature: Tracking Protection {web link}

A reinstall should be fresh though? Does safe mode disable other innate FF features that may be causing this? Also, how does safe mode affect stored sessions? I would hate to lose my current tabs.

Hi, Safe Mode is safe. Should not loose anything, it should tell us a few things. Please also referto Fred's URL for taracking :

• https://support.mozilla.org/kb/Safe+Mode
• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

In Firefox Safe mode these changes are effective:

• all extensions are disabled (about:addons)
• default theme is used (no persona)
• userChrome.css and userContent.css are ignored (chrome folder)
• default toolbar layout is used (file: localstore-safe.rdf)
• Javascript JIT compilers are disabled (prefs: javascript.options.*jit)
• hardware acceleration is disabled (Options > Advanced > General)
• plugins are not affected
• preferences are not affected

TEST''''is issue still there ?

This is diagnostic only but you should be prepared to loose sessions if have to repair further.

• https://support.mozilla.org/en-US/kb/export-firefox-bookmarks-to-backup-or-transfer
• https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles

Hi, please go to the Firefox 3 Bar Menu --> Options --> Privacy & Security panel and under Permissions check the setting to Prevent Accessibility Services from accessing your browser. Restart Firefox

Pardon the late answer, the issue is absent right now, but I've no doubt it will return, as it always does. It's a pain to troubleshoot too, since I've yet to discover a pattern to when it happens and what could possibly trigger it. Accessbility has long since been disabled, forgot to mention that.

Note that Firefox can become slow if you run out of memory and the OS starts swapping to the Windows page file. If it happens again then check on the about:memory page how much memory Firefox is using. You may have to close and restart Firefox (note that there is a restart button on the about:profiles page).

You can open "about:" pages via the location/address bar like you open a web page.

• "about:" is a protocol to access special pages

I can not find any numbers of any kind on the about:memory page, unless I press the "measure" button under "show memory reports", which I don't know how to read as it seems to show what is allocated where(?) rather than how much. Also, as this may happen right after booting up or 12 hours after booting, I don't think it's related to memory.

Are you using Sync?

You can check for problems with the places.sqlite database (bookmarks and history) in the Firefox profile folder.

• use "Verify Integrity" on the "Help -> Troubleshooting Information" (about:support) page

See also:

• http://kb.mozillazine.org/Locked_or_damaged_places.sqlite
• https://support.mozilla.org/en-US/kb/Bookmarks+not+saved#w_fix-the-bookmarks-file