The "issues" you've mentioned are intentional changes to Firefox's behavior for privacy.

By "Firefox opens minimized", I assume you mean that even when you maximize Firefox the page doesn't use the entire window. This makes it harder for websites that try to track you based on the size of the page you view.

Websites track your accounts using cookies. If you want to stay logged in to your accounts, you'll have to allow some cookies and make sure they are not deleted once you close Firefox.

I suggest you at least take the time to read and understand what some of those about:config tweaks both on that site and in the user.js actually do. You'll then be able to make a choice between privacy or convenience caused by those settings

These two pref changes are likely mentioned. This pref prevent saving a maximized window and uses rounded values for the window dimensions.

• privacy.resistFingerprinting = true

This pref prevents Firefox from storing cookies for open tabs as part of session restore.

• browser.sessionstore.privacy_level = 2

You made so many changes to important prefs that best is to rename/remove prefs.js to undo all changes you made and start with a fresh Firefox customization. Like posted above, it is not a good idea to make changes to prefs without fully understanding what these prefs are about and knowing the consequences. Many of the tweaks that are posted on internet aren't changes we would recommend.

If you have created a user.js file in the profile folder then remove this file as well with Firefox closed.

You can use the button on the "Help -> Troubleshooting Information" (about:support) page to go to the current Firefox profile folder or use the about:profiles page.

• Help -> Troubleshooting Information -> Profile Folder/Directory:
  Windows: Open Folder; Linux: Open Directory; Mac: Show in Finder
• https://support.mozilla.org/en-US/kb/profiles-where-firefox-stores-user-data

Your system details show User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:68.0) Gecko/20100101 Firefox/68.0 ... which is likely based on the privacy.resistFingerprinting preference being set to true (among other changes that setting makes). See Firefox's protection against fingerprinting to learn what this preference does and how to reset it back to the default "false" setting.

Your best bet, like cor-el suggests, is reset all preference settings. See Reset Firefox preferences to troubleshoot and fix problems Solution 2 (delete or rename the prefs.js file, and user.js file if found).

If problems persists or it is too much effort to undo all changes then you can consider to create a new profile.

See "Creating a profile":

• https://support.mozilla.org/en-US/kb/profile-manager-create-remove-switch-firefox-profiles

If the new profile works then you can transfer files from a previously used profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over problems.

• https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile

Hi guys,

So thanks for all the replies! So, after I changed privacy.resistFingerprinting to false and browser.sessionstore.privacy_level to 0 My firefox opens in full screen window know when I open it. But it still logs me out of all my accounts. Although I don't really want to make a new profile, because I believe that those settings on that website, actually helps for your privacy.

Kind regards,

Crewz

If you don't want to create a new profile or reset all preferences because you are just concerned about Firefox logging you out of your accounts when closed and restarted, go through all of your Privacy & Security settings and make sure you are not deleting cookies and site data when Firefox is closed. You can also follow the suggestions posted here:
https://support.mozilla.org/en-US/questions/1203650 Firefox signs me out of websites when closed, which I would like to turn off.