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Firefox doesn't open web sites but gives 404 reference instead & Web mail issues.

  • 2 replies
  • 1 has this problem
  • 2269 views
  • Last reply by cor-el

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Software versions used: Mac OS 10.12.6. Firefox 55.0.3. Safari 10.1.2.

Problem: I get 404 page not found references when I follow links in email correspondence and in searches. When I do the SAME links in Safari I get the page. I'm also having issues with my Web mail settings where parts of the settings disappear when forwarding, replying, or composing email when I use HTML/plain text email. I have uploaded example images of each of these conditions. I have none of these issues when I use Safari.

What I have done: 1. Spent hours reading Firefox "how-to" files. 2. Cleared history, cache, and cookies with no change. 3. Downloaded and substituted the Beta version (56) of Firefox without change. 4. Trashed and re-downloaded Firefox current edition approx. 3 times both before and after the Beta version.

At this point I have no idea how to fix this. I am being forced to change my default browser to Safari which does not display the tabs, etc. in a way I prefer.

How do I fix this or is it something I can fix?

Attached screenshots

Chosen solution

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?


Start your Computer in safe mode. Then start Firefox. Try Safe websites. Is the problem still there?

http://encyclopedia2.thefreedictionary.com/Linux+Safe+Mode Starting Any Computer In Safe Mode; Free Online Encyclopedia

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Chosen Solution

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?


Start your Computer in safe mode. Then start Firefox. Try Safe websites. Is the problem still there?

http://encyclopedia2.thefreedictionary.com/Linux+Safe+Mode Starting Any Computer In Safe Mode; Free Online Encyclopedia

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If you use a bookmark then navigate to the web page starting with the main page or the sign in page in case there is a problem with this bookmark.

You can remove all data stored in Firefox from a specific domain via "Forget About This Site" in the right-click context menu of an history entry ("History -> Show All History" or "View -> Sidebar -> History").

Using "Forget About This Site" will remove all data stored in Firefox from that domain like bookmarks and history and cookies and passwords and cache and exceptions, so be cautious. If you have a password or other data from that domain that you do not want to lose then make sure to backup this data or make a note.

You can't recover from this 'forget' unless you have a backup of involved files.

If you revisit a 'forgotten' website then data from that website will be saved once again.