Does starting Thunderbird in https://support.mozilla.org/en-US/kb/safe-mode help?

Hi there Wayne Mery, Thank you very much your suggestion worked – Going to safe mode did the trick. At first I thought it didn’t but a couple of clicks and away it went. My PC seemed to come good after my usual PHAMTON fiddling, but my wife’s did not. I have used Mozila suit 1st away back when – Then Firefox and SeaMonkey now Firefox & Thunder bird - this is the first time I have a problem I could not fix. Been the best software. Thank you for the help

In that case, you want to look at tools | addons | extensions and experiment to find and tell us which addon is causing your problem.

Hi There Wayne Mery, The only Add On that I could see has been stopped as not being compatible with Thunderbird 45.1.0 is Silvermel and Charamel XT 1.6.1 – Possible VLC Web Plugin 2.2.1.0 as well??

This isn't about what is stated in the UI regarding compatibility - which cannot be fully trusted. It's about testing each addon.

Plugins we don't care about (generally)

Hi there Wayne, The only 2 extensions on PC 2 are Lightning and Thunderbird Conversations. There were 2 others I seen whilst in safe mode that had been disabled as incompatible with 45.0.1 – without taking too much notice what they were I removed them. Regards George