What page opens instead of the home page?

You can check the startup setting.

• Tools > Options > General > Startup: "When Firefox starts":
  "Show my windows and tabs from last time"
  "Show my home page"
  "Show a blank page"

You can check if you have a user.js file in the Firefox profile folder that sets the browser.sessionstore.resume_session_once pref to true.

• http://kb.mozillazine.org/browser.sessionstore.resume_session_once

You can check for problems with the sessionstore.js file in the profile folder that stores session data. When sessionstore.js is deleted you lose pinned tabs and Tab Groups and open tabs and you will have to recreate them, so if necessary make a note or bookmark them.

You can use this button to go to the current Firefox profile folder:

• Help > Troubleshooting Information > Profile Directory:
  Windows: Show Folder; Linux: Open Directory; Mac: Show in Finder
• http://kb.mozillazine.org/Profile_folder_-_Firefox

Are you getting a blank page instead of your home page? If you have Firefox set to clear history when it closes, the problem could be due to a bug in Firefox 44 which will be fixed in Firefox 45 (scheduled to be released next week).

You can try to minimize the frequency of the problem by allowing Firefox time to shut down normally by using Exit from the menu instead of using the red "X" button or having Windows shut down Firefox. Either:

• "3-bar" menu button > "power" button
• (menu bar) File > Exit

Today when I opened firefox the tabmix plus addon updated automatically and now my home page opens as it should.

well, today it started happening again. Hopefully the firefox update will fix it for god