Tools menu (alt+T) > add-ons. Click on the "extensions" entry on the left.

Is Lightning showing in the list? If not, it is not installed. Type lightning in the search box on the top right and press enter and install lightning

Hi Matt: Thanks for your reply. The extension list has lightening 3.3.3 and and provider for google calendar 1.04 but the options button is not there for provider. If lightening is the way to get my google calendar, and it is listed but doesn't seem to do anything, what am I missing? Is there something in addition to Lightening to bring the calendar in? I very much appreciate your help. Thanks in advance.

'Update': I found an extension called Google Calendar Tab - installed, and worked instantly. Thanks again for your help.

I just updated to TB 38.0.1 from 37. During the update it said that Lightening 3.3.3 wasn't compatible and I allowed it to download Lightening v4. But it stalled while "installing" and then froze.

Exited TB and manually tried to download/install Lightening from the link offered on the Add-On screen. Nothing happens when I click that link and after exiting/restarting TB again, Lightening is not listed on my extensions page.

Now what? I need my calendar back ASAP!

Update:

I manually downloaded the Lightening v4 .xpi file from here to my hard drive. I then searched for it from the TB38 add-in page and allowed it to install.

It said to restart TB to complete the install but It didn't install the first time. I repeated the entire process again and the second time it installed.

So there's something flaky about the link that TB38 offers for Lightening 4 on the add-in page and there's something flaky about installing it in TB38.

Win 7 Pro+SP1 (32-bit)