Safe Mode is a troubleshooting mode that temporarily turns off hardware acceleration, resets some settings, and disables add-ons (extensions and themes). If the problem goes away, that tells us one thing. If it does not, that tells us something else.

Type about:preferences#advanced<Enter> in the address bar.

Under Advanced, Select General. Look for and turn off Use Hardware Acceleration.

Poke around safe web sites. Are there any problems?

Type about:addons<enter> in the address bar to open the Add-ons Manager. Hot key; <Control>(Mac=<Command>) <Shift> A)

On the left side of the page, select Appearance. Then select Default.

Responding to FredMcD.

Thank you FredMcD. Your suggestions did not solve my problem.

I tried as you suggested in sequence. Neither reenabled FF's ability to connect to the 'Net.

Restarting FF in safe mode restores FF's ability to connect to the net.

The website I tried to get to was www.google.com

If it works in Safe Mode and in normal mode with all extensions (3-bar Menu button/Tools > Add-ons > Extensions) disabled then try to find which extension is causing it by enabling one extension at a time until the problem reappears.

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

Close and restart Firefox after each change via *3-bar Menu button > Exit (Power button)

• Windows: File > Exit
• Mac: Firefox > Quit Firefox
• Linux: File > Quit

You can check for problems with preferences.

Delete possible user.js and numbered prefs-##.js files and rename (or delete) the prefs.js file to reset all prefs to the default value including prefs set via user.js and prefs that are no longer supported in current Firefox releases.

• http://kb.mozillazine.org/Preferences_not_saved
• http://kb.mozillazine.org/Resetting_preferences

You can use this button to go to the current Firefox profile folder:

• Help > Troubleshooting Information > Profile Directory: Show Folder (Linux: Open Directory; Mac: Show in Finder)
• http://kb.mozillazine.org/Profile_folder_-_Firefox

cor-el said

If it works in Safe Mode and in normal mode with all extensions (3-bar Menu button/Tools > Add-ons > Extensions) disabled then

It works in safe mode. It does not work in normal mode with all extensions disabled.

Are there extensions appearing in about:addons that you do not see in normal mode or extensions that do not have a Remove button?

Create a new profile as a test to check if your current profile is causing the problem.

See "Creating a profile":

• https://support.mozilla.org/kb/profile-manager-create-and-remove-firefox-profiles
• http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Profile_issues

If the new profile works then you can transfer files from a previously used profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over problems.

• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

cor-el said

You can check for problems with preferences. Delete possible user.js and numbered prefs-##.js files and rename (or delete) the prefs.js file to reset all prefs to the default value including prefs set via user.js and prefs that are no longer supported in current Firefox releases.

• http://kb.mozillazine.org/Preferences_not_saved
• http://kb.mozillazine.org/Resetting_preferences

You can use this button to go to the current Firefox profile folder:

• Help > Troubleshooting Information > Profile Directory: Show Folder (Linux: Open Directory; Mac: Show in Finder)
• http://kb.mozillazine.org/Profile_folder_-_Firefox

Ok ... a little bizarre now.

I renamed prefs to prefs.hold.

I restarted FF.

FF would not connect to the Internet.

I deleted prefs.

I renamed prefs.hold back to prefs.

Now FF is connecting.

Strange.

RalphShnelvar said

cor-el said

Ok ... a little bizarre now. I renamed prefs to prefs.hold. I restarted FF. FF would not connect to the Internet. I deleted prefs. I renamed prefs.hold back to prefs. Now FF is connecting. Strange.

And then I logged out of FF and back in again ... Same problem. I need to be in safe mode to get it to work.

Sigh.

What are the connection settings?

• Tools > Options > Advanced > Network : Connection > Settings
• https://support.mozilla.org/kb/Options+window+-+Advanced+panel

If you do not need to use a proxy to connect to internet then try to select "No Proxy" if "Use the system proxy settings" or one of the others do not work properly.

See "Firefox connection settings":

• https://support.mozilla.org/kb/Firefox+cannot+load+websites+but+other+programs+can

Boot the computer in Windows Safe Mode with network support (press F8 on the boot screen) to see if that helps.

• http://www.bleepingcomputer.com/tutorials/how-to-start-windows-in-safe-mode/
• http://www.7tutorials.com/4-ways-boot-safe-mode-windows-10

Create a new profile as a test to check if your current profile is causing the problem.

See "Creating a profile":

• https://support.mozilla.org/kb/profile-manager-create-and-remove-firefox-profiles
• http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Profile_issues

If the new profile works then you can transfer files from a previously used profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over problems.

• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

RalphShnelvar said

RalphShnelvar said

cor-el said

Ok ... a little bizarre now. I renamed prefs to prefs.hold. I restarted FF. FF would not connect to the Internet. I deleted prefs. I renamed prefs.hold back to prefs. Now FF is connecting. Strange.

And then I logged out of FF and back in again ... Same problem. I need to be in safe mode to get it to work.

Sigh.

A little more bizarre now. I attempted to start FF (not in safe mode, I think) ... and FF refused to start. I needed to reboot my system to get FF to start again.

cor-el, I will now try your suggestions about connection settings.

cor-el said

What are the connection settings?

• Tools > Options > Advanced > Network : Connection > Settings
• https://support.mozilla.org/kb/Options+window+-+Advanced+panel

If you do not need to use a proxy to connect to internet then try to select "No Proxy" if "Use the system proxy settings" or one of the others do not work properly.

Dear god (or the god-like corel)!

Setting "no proxy" seems to have cleared the problem!

I made no changes to any network setting in the last few days except, of course, the change you recommended.

Let's not mark this as solved yet as it may be a coincidence.

You're welcome.

Do you still remember what the previous connection settings were?

cor-el said

Do you still remember what the previous connection settings were?

I believe it was "Use System Proxy Settings"

I see in my current prefs.js: user_pref("network.proxy.type", 0);

I took an image backup of my system yesterday before I started fiddling with changes.

When I look at prefs.js from yesterday, there is no "user_pref("network.proxy.type", 0);" line so I guess it takes whatever the default is. What is the default?

Value "0" is the "No Proxy". The default is 5: "Use the system proxy settings"

• http://kb.mozillazine.org/network.proxy.type

Sadly, the change to "no proxy" only solved the problem temporarily.

To repeat the symptoms:

• FF seems to work fine in safe more. It is able to connect to the 'Net. In normal mode it does not.
• Sometimes FF refuses to start.
• Sometimes FF refuses to add a new window (not tab)
• Disabling all addons and plugins does not cure the problem when restarting FF
• New symptom: Adobe flash crashes a lot when installed and enabled. I have uninstalled Adobe flash and am still having problems.
• If I reinstall FF, FF connects to the 'Net the first time and then does not.

Explorer and Chrome have no problems connecting to the 'Net.

Create a new profile as a test to check if your current profile is causing the problem.

See "Creating a profile":

• https://support.mozilla.org/kb/profile-manager-create-and-remove-firefox-profiles
• http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Profile_issues

If the new profile works then you can transfer files from a previously used profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over problems.

• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

So I create a new profile.

FF works in safe mode. In normal mode it refuses to connect to the 'Net.

Chrome and IE does not have this problem.

- - -

From my old profile, I exported the bookmarks to an HTML file.

I am unable to import the bookmarks to the new profile.

I installed FF X64. I am unable to import the bookmarks there either.

Let me see if FF X64 has the same connectivity issue.

I have a work-around that worked for me.

I uninstalled FF-x86

I installed FF-x64

I created a new profile using

 firefox.exe -p

then

 I copied over the profile which did not work on FF-x86.

All is well now.

Note. The old profile had the proxy set to system. This works, as well.

Let's keep this open for a couple of day to see if this really resolved the issue.

Hi,

I have had similar issue. Just wondering, do you have NVidia video card? Not that it should be related but I found information that v44, 32-bit has issue with NVidia video cards and DNS.

msholind said

Hi, I have had similar issue. Just wondering, do you have NVidia video card? Not that it should be related but I found information that v44, 32-bit has issue with NVidia video cards and DNS.

Yes, I have an NVIDIA video card. Could you please provide a link to the problem?

- - -

My solution posted on 2/5/16, 5:39 PM seems to be working.

The link to Mozilla bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1243765

Comment #1 ( philipp ) seems to correlated several similar reported issues to NVidia video card. Hopefully Mozilla support team can confirm all these similar issues are related to NVidia GPU.