Hello Colintoo,

yes, firefox 39 is not...fully compatible with windows 10, there are inconsistencies in the theme, and some other bugs that make it a less than great experience :(.

Firefox 40 fixes these issues ( https://www.mozilla.org/en-US/firefox/40.0beta/releasenotes/ ), please try the beta version (ff 40) and tell us again if you have any other problems :

• https://www.mozilla.org/en-US/firefox/beta/all/

thank you, and sorry for the inconvenience

EDIT Firefox 40 will release, stable in August 11th

thanks again

Colintoo said

Hi Have just updated Windows 8.1 to 10 and Firefox will not start anymore showing: Firefox is already running, but is not responding. The old Firefox process must be closed to open a new window. If I choose to close nothing happens. I've been through the Kb but can find no firefox processes running. I've uninstalled Firefox twice and removed all traces then re installed but the problem persist. Any clues? Thanks.

ideato said

Hello Colintoo, yes, firefox 39 is not...fully compatible with windows 10, there are inconsistencies in the theme, and some other bugs that make it a less than great experience :(. Firefox 40 fixes these issues ( https://www.mozilla.org/en-US/firefox/40.0beta/releasenotes/ ), please try the beta version (ff 40) and tell us again if you have any other problems :

• https://www.mozilla.org/en-US/firefox/beta/all/

thank you, and sorry for the inconvenience EDIT Firefox 40 will release, stable in August 11th thanks again

Thanks for the prompt response. Tried the beta but sadly the same problem is still happening. I'll wait for the release on August 11.

Have you tried restarting the computer?

Ref: "Firefox is already running but is not responding" error - How to fix

If you can't fix it by removing the parent.lock file then try to 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

• C:\Users\<user>\AppData\Roaming\Mozilla\Firefox\Profiles\<profile>\

"AppData" (XP: Application Data; Mac: ~/Library; Linux: ~/.mozilla) is a hidden folder.

• http://kb.mozillazine.org/Show_hidden_files_and_folders

Thanks Cor-el

Will try this when I get a moment but in the meantime I've had to switch to edge. Strangely IE which initially worked fine is now refusing to load.

Hi, please see the next, if it helps : http://www.tenforums.com/network-sharing/10028-internet-connection-only-microsoft-edge.html

thank you

Colintoo said

<snip> in the meantime I've had to switch to edge. Strangely IE which initially worked fine is now refusing to load.

I saw multiple threads posted about internet connectivity issues in this Windows 10 forum: http://www.tenforums.com/network-sharing/

The following thread links to Microsoft's article, Cumulative Update for Windows 10: August 5, 2015 (KB3081424) that was just released, so I would try that first:

http://www.tenforums.com/network-sharing/13174-kb3081424-resolves-ethernet-connectivty-issues.html KB3081424 resolves ethernet connectivty issues