• Make sure that you not run Firefox in Private Browsing - Use Firefox without saving history mode
• You are in Private Browsing mode if you see "Tools > Stop Private Browsing", possibly grayed

• You enter Private Browsing mode if you select: Tools > Options > Privacy > History: Firefox will: "Never Remember History"
• To see all History settings, choose: Tools > Options > Privacy, choose the setting Firefox will: Use custom settings for history
• Uncheck: [ ] "Automatically start Firefox in a private browsing session"

You can also export the bookmarks to an HTML file in the brwoser that you want to import the bookmarks from and import that file in Firefox.

• Import the HTML file in Firefox: Bookmarks > Organize Bookmarks > Import & Backup > Import HTML: From File

See also http://kb.mozillazine.org/Import_bookmarks ("Import from another browser" and "Import from file")

Thanks. Before I saw your reply, I uninstalled then reinstalled FF. Your way probably would have been easier.

It worked. Unchecked Private Browsing in Preferences and Import is no longer grayed out.