I assume you do not have Firefox set to Restore Previous Session on the Settings page?

Otherwise, this screen appears if:

(A) Firefox detects at startup that it did not shut down normally -- this is treated as a crash scenario and Firefox tries to recover by automatically restoring your last session

(B) The automatic session restore failed -- Firefox asks if you want to try that again with some or all of the tabs, or start a new session

Note: the automatic session restore step will be skipped and Firefox goes straight to (B) if you modified browser.sessionstore.max_resumed_crashes to zero in about:config (normally this is set to 1).

Some reasons that Firefox might think it crashed:

(1) You "kill" Firefox in the Windows Task Manager ("End Process" for example)

(2) Firefox doesn't have enough time when it is shutting down to update all of its files -- I suggest pausing for 30-60 seconds after using Exit (from the main menu or File menu) before shutting down Windows

(3) Clean-up software is removing the sessionstore.jsonlz4 (session history) file between sessions or making other changes to your Firefox data

I have had this problem for months. I have searched for and asked for solutions, and nothing that I have been told to do has solved this problem. I am convinced that there is absolutely nothing I can do to solve it. The only way for this problem to be solved is for Mozilla to solve it and put out an update.

There's no good reason for this "feature" even to exist. Some code you have inserted into the program is causing this. You need to find it and delete it.

Where did you ask? I don't see the thread on this site.

I suspect there is something unusual about your settings, add-ons, system, or other factors. For example, you might have a user.js file instructing Firefox to restore your last session at startup. I say this not because I don't care about your inconvenience, but because this is just not a common complaint in recent years. We should try to get to the bottom of it, no? If you were to file a bug report with this information, I don't think it would be enough to lead to a specific change in Firefox.

Perhaps as a temporary workaround, it would help to completely turn off crash recovery. You can try this setting:

(1) In a new tab, type or paste about:config in the address bar and press Enter/Return. Click the button accepting the risk.

(2) In the search box in the page, type or paste browser.sessionstore.resume_from_crash and pause while the list is filtered

(3) Double-click the preference to switch the value from true to false

Even with this setting, you still could manually restore your previous session from the menu. Either:

• "3-bar" menu button > History > Restore Previous Session
• (menu bar) History > Restore Previous Session

Does that make any difference in how your Firefox starts up?