What type of calendar do you have - local or network? If network, is it a Google Calendar? If Google, how do you access it - via Provider extension or CalDAV?

Thank you for getting back to me. I have a network calendar that is a Google Calendar. I access it in Lightning by using the add on Provider for Google Calendar 0.25. When setting up the Google Calendar Access I use the extension that is provided in my Google Calendar. This App works fine, it is only when I enable Lightning that everything freezes. And it opens, freezes within 30 seconds and never unfreezes. I have to use Task Manager to exit the program and then open by disabling add ons in order to get it to work.

FYI, I just tried to enable Lightning again and opened it and now it is working. It froze for about 30 seconds, but then started working. It seems to be an intermittent problem, as this occurred before and it lasted for about a month and then it started again a couple weeks ago and has lasted until today. Please advise on if you can suggest anything that can prevent this in the future. Thanks.

The only time I've seen Thunderbird becoming unresponsive was when it hasn't been started for a week or longer. Upon starting it then took a while for Lightning do it's thing, and then returned back to normal.

What is your anti-virus software?

AVG is my firewall/anti-virus

Try to start *Windows* in safe mode with networking enabled.

- Win8 http://windows.microsoft.com/en-US/windows-8/windows-startup-settings-including-safe-mode

- Win7 http://windows.microsoft.com/en-US/windows7/Start-your-computer-in-safe-mode

- XP http://www.microsoft.com/resources/documentation/windows/xp/all/proddocs/en-us/boot_failsafe.mspx

Still in Windows safe mode, start Thunderbird in safe mode.

- https://support.mozilla.org/en-US/kb/safe-mode

Does the problem go away?

I understand your request, but as I mentioned above I am not experiencing the problem so if I did this the problem would not occur then also. I don't know why it started working again, but as of right now it is working. Further, when the problem did occur starting Thunderbird in SafeMode did allow it to work okay. Not sure what is left to do if I can't currently replicate the problem.

Got you. You can try Windows safe mode in case the problem comes back.