Are you shutting down the computer properly, or just hitting the power switch? If the latter, computers don't like that. It could cause damage to the hard drive. Not to mention programs won't be able to save their data.

Note: If you don't shut down Firefox properly, it may think it crashed and try to restore the previous session.

On Linux, Firefox has a special integration with the OS: if Linux sends Firefox a message to close because the system is shutting down, then Firefox will set a flag to do an automatic session restore the next time you start it. (I've lost track of the thread where I posted the details on this.)

I'm not aware of a workaround for bypassing that, but maybe someone else has heard of one.

Thia might be about the presence and content of sessionCheckpoints.json in the profile folder.

See also:

• about:config => browser.sessionstore.resume_session_once
• resume_session_once and onQuitApplication:
  https://searchfox.org/mozilla-release/source/browser/components/sessionstore/SessionStore.jsm#line-2194

Are you shutting down the computer properly, or just hitting the power switch? If the latter, computers don't like that. It could cause damage to the hard drive. Not to mention programs won't be able to save their data. Note: If you don't shut down Firefox properly, it may think it crashed and try to restore the previous session.

Im shutting down properly =]

On Linux, Firefox has a special integration with the OS: if Linux sends Firefox a message to close because the system is shutting down, then Firefox will set a flag to do an automatic session restore the next time you start it. (I've lost track of the thread where I posted the details on this.) I'm not aware of a workaround for bypassing that, but maybe someone else has heard of one.

See also:

• about:config => browser.sessionstore.resume_session_once
• resume_session_once and onQuitApplication:
  https://searchfox.org/mozilla-release/source/browser/components/sessionstore/SessionStore.jsm#line-2194

config => browser.sessionstore.resume_session_once it was false, i turned into true, nothing happened. should i delete sessionCheckpoints.json?

cor-el dijo

See also:

• about:config => browser.sessionstore.resume_session_once
• resume_session_once and onQuitApplication:
  https://searchfox.org/mozilla-release/source/browser/components/sessionstore/SessionStore.jsm#line-2194

config => browser.sessionstore.resume_session_once it was false, i turned into true, nothing happened. should i delete sessionCheckpoints.json?

The preference is always reset to false after the "one time restore." The problem is that it is getting set to true during shutdown. I suppose in theory you could try using a user.js file to permanently override preference to false. This could be a problem during updates and other restarts where restoring your session is normal.

What is the content of sessionCheckpoints.json when you force Firefox to close this way ?