How do I make Firefox 13 Load All My Tabs on Startup or when Resuming Reload

You can turn off the new default setting within the options panel.

• Open the Firefox menu by clicking the Firefox button

• Select Options

• On the General Tab click the option drop-down next to When Firefox starts: and choose Show my windows and tabs from last time

• Uncheck Don’t load tabs until selected option and press OK

One small addition to Jeremy's answer is that after you've unchecked the checkbox, you can switch back to one of the other options in that dropdown and keep the setting.

This is useful for people that don't save their tabs by default in cases like restarts caused by extension installations where your tabs do get saved.

And if you're using Tab Mix Plus (TMP), you need to go to TMP Options > Session > Restore and check the "Reload all tabs" checkbox (which respects the Load Tabs Progressively add-on if you're also using it).

Not sure about what needs to be done if you're using the Session Manager add-on.

/kim