• Start Windows in safe mode with networking enabled - https://support.microsoft.com/en-us/help/12376/windows-10-start-your-pc-in-safe-mode
• Still In Windows safe mode, start Thunderbird in Troubleshoot Mode - https://support.mozilla.org/en-US/kb/troubleshoot-mode-thunderbird

Does problem change? (many users have found antivirus software causing problems)

If it did not get better, try changing the hidden preference accessibility.force_disabled to 1.

Please post your results. Thanks

Wayne, This did not solve my problem. I'm not exactly sure that I followed all the instructions properly. I am using Norton Antivirus and security/privacy software.

I would like to try the last procedure, but am unsure of where to find this or how to acces to make these changes: "If it did not get better, try changing the hidden preference accessibility.force_disabled to 1."

Wayne, This did not solve my problem. I'm not exactly sure that I followed all the instructions properly. I am using Norton Antivirus and security/privacy software. I would like to try the last procedure, but am unsure of where to find this or how to acces to make these changes: "If it did not get better, try changing the hidden preference accessibility.force_disabled to 1."

Settings > General > Config Editor