Please explain the problem in detail. What happens? What is/are the exact error message(s) ?

Hi

I'm using some sites with pined tab when the browser is close from any reason, the tab's that was open in the last session not open I'm getting only one empty tab

In case you use "Clear history when Firefox closes".

• do not clear the Browsing History

• Settings -> Privacy & Security
  Firefox will: "Use custom settings for history":
  [X] "Clear history when Firefox closes" -> Settings
• https://support.mozilla.org/en-US/kb/delete-browsing-search-download-history-firefox

• clearing "Site Preferences" clears exceptions for cookies, images, pop-up windows, and software installation and exceptions for passwords and other website specific data
• clearing "Cookies" will remove all cookies including cookies with an allow exception you may want to keep