We're sorry to hear that your Firefox seems to be crashing when you open it. Please perform the following steps to give us a crash report ID that helps us find out more about the cause of the crash.

1. On the keyboard, press [Windows] The image "Windows key" does not exist. + [R]. This should bring up a Run window that contains a text field.
2. In that text field, type %APPDATA% and press Enter. An explorer window should open.
3. From that explorer window, double-click on the Mozilla folder, then double-click on Firefox and then on Crash reports. Double-click on submitted.
4. Now, you should see a list of files that contain reports. Go to View > Arrange Icons by > Modified to get the most recent files at the top of the window.
5. Open the most recent 5 files with a text editor and copy the IDs.
6. Paste each ID with bp- into the reply window on the forums.

Thanks in advance!

You can find more information and troubleshooting steps in the Troubleshoot Firefox crashes (closing or quitting unexpectedly) article.

Here are the IDs of the crash reports as requested:

bp-3369966c-7044-4dbe-8007-46b632150730 bp-15929173-bdca-4d74-a0c4-5ebdb2150730

By the way, I`m using a pc.

Thank you !

thank you, this appears to be an issue caused by trusteer rapport on your computer. please see if there's an update available for that program or else remove it for the moment and report it to trusteer's support at https://www.trusteer.com/support/submit-ticket

I got in touch with Rapport and they don`t support Windows 10 at the moment. I therefore uninstalled Rapport and now Firefox works as usual ! All good - except I`ve now lost Adobe Flash !! More work for tomorrow.