hello, could you provide your latest few submitted crash reports? please enter about:crashes into the location bar, copy the latest few report ids from there starting with bp- & paste them here into a forum reply. this will give us a better understanding what may be triggering those crashes.

Hello, Thanks for getting back to me. The last few I have are bp-017c8178-efae-4b58-9214-9fad72160309 bp-d79a7ca3-5c7d-4cb5-a40b-70cfc2160309 bp-a2825172-e644-45e9-a7f9-9bda02160309

thank you for following up. unfortunately those crashes appear to be caused by trusteer rapport which is running on your device and hooking into firefox - please check that you are fully updated there or temporarily disable/uninstall that software for the moment.

please also get in contact with trusteer's support which are usually very quick to respond and fix issues like this: https://trusteer.secure.force.com/PKB/articles/en_US/FAQ/browser-crashes

Thanks, I was fairly sure it was that which was causing it as it's happened many times before. I updated the software this morning, so I'll drop them a line and take it from there. Thanks again for your help, Mark