I don't think importing bookmarks should cause any problems. But I wonder whether the import also included your IE cookies, and those replaced your Firefox cookies for the same sites, or they got mixed together. That could cause sites to kick you out and make you log in again.

I don't know why the Facebook Container add-on would stop working. Is it still enabled? You can check on the Add-ons page. Either:

• Ctrl+Shift+a (Mac: Command+Shift+a)
• "3-bar" menu button (or Tools menu) > Add-ons
• type or paste about:addons in the address bar and press Enter/Return

In the left column of the Add-ons page, click Extensions.

Then scan down the right side. Any disabled extensions cluster at the bottom.

Also, any extensions Firefox installs for built-in features are hidden from this page, so everything listed here is your choice (and your responsibility) to manage. Anything suspicious or that you just do not remember installing or why? If in doubt, disable (or remove).

Since you mention that login cookies don't survive when you exit Firefox and start it up again, perhaps you should double-check your cookie and history settings on the Options page:

• Windows: "3-bar" menu button (or Tools menu) > Options
• Mac: "3-bar" menu button (or Firefox menu) > Preferences
• Linux: "3-bar" menu button (or Edit menu) > Preferences
• Any system: type or paste about:preferences into the address bar and press Enter/Return to load it

In the left column, click Privacy & Security

Automatic Private Browsing?

On the right side, in the History section, either of these will trigger automatic private browsing, so no history (including cookies) is retained when Firefox is closed:

• "Firefox will: Never remember history"
• "Firefox will: Use custom settings for history" + "Always use private browsing mode"

If you have either of those set, change to "Firefox will: Remember history" or uncheck the box for "Always use private browsing mode".

Clearing history at shutdown?"

Select: Firefox will: Use custom settings for history so you can view the detailed settings. Then check this setting:

• "Clear history when Firefox closes" -- not checked, ok

• "Clear history when Firefox closes" -- checked => click the Settings button and make sure "Cookies" is NOT set to be cleared

Cookie lifetime?

In the Cookies and Site Data section, check your cookie "lifespan" setting:

• Keep until: they expire -- allows sites to set persistent cookies
• Keep until: Firefox is closed -- only allows sites to set session cookies (cleared when exiting Firefox) unless the site has an "Allow" in the Exceptions list

Did you make any changes? If so, does that help?