browser.tabs.unloadOnLowMemory=true  
   browser.tabs.min_inactive_duration_before_unload=60000
    

   System Memory:  Automatic tab discarding only occurs when Firefox detects low memory conditions. If your system has sufficient memory available, Firefox may not trigger the discarding process.  
   Setting Behavior:  The min_inactive_duration_before_unload value (set to 60000 ms, or 1 minute) might be too short for Firefox to effectively discard tabs. Consider increasing this value to something like 300000 ms (5 minutes) to see if it makes a difference.
    

   Firefox saves your session data (including open tabs) by default to restore them after a restart. This means that even if you manually discard a tab, its state is still part of the saved session unless explicitly closed.  
   To prevent discarded tabs from reappearing, you can adjust the following settings in about:config:  
       Set browser.sessionstore.restore_on_demand to true. This ensures that tabs are only restored when you interact with them.  
       Alternatively, set browser.startup.page to 0 (blank page) to disable session restoration entirely.
        
    

   Use the "Suspend Inactive Tabs"  feature from extensions like Auto Tab Discard   for more granular control over tab discarding.  
   Regularly update Firefox to ensure you’re benefiting from the latest performance improvements.
    

Hello, Thank you for reaching out with your question regarding Firefox tab discarding. Based on the details you’ve provided, I’ll address your concerns step by step: 1. Automatic Tab Discarding Not Working You mentioned that tabs are not being discarded automatically, even though you’ve enabled the following settings in about:config: browser.tabs.unloadOnLowMemory=true browser.tabs.min_inactive_duration_before_unload=60000 These settings are intended to help Firefox automatically discard inactive tabs when the system is low on memory or after a specified duration of inactivity. However, there are a few things to consider: System Memory: Automatic tab discarding only occurs when Firefox detects low memory conditions. If your system has sufficient memory available, Firefox may not trigger the discarding process. Setting Behavior: The min_inactive_duration_before_unload value (set to 60000 ms, or 1 minute) might be too short for Firefox to effectively discard tabs. Consider increasing this value to something like 300000 ms (5 minutes) to see if it makes a difference. 2. Manually Discarded Tabs Restoring After Restart You also mentioned that when you manually discard tabs using about:unloads, they reappear after restarting Firefox. This behavior is expected due to how Firefox handles session restoration: Firefox saves your session data (including open tabs) by default to restore them after a restart. This means that even if you manually discard a tab, its state is still part of the saved session unless explicitly closed. To prevent discarded tabs from reappearing, you can adjust the following settings in about:config: Set browser.sessionstore.restore_on_demand to true. This ensures that tabs are only restored when you interact with them. Alternatively, set browser.startup.page to 0 (blank page) to disable session restoration entirely. 3. Additional Recommendations If you’re looking to optimize Firefox’s memory usage further, consider the following: Use the "Suspend Inactive Tabs" feature from extensions like Auto Tab Discard for more granular control over tab discarding. Regularly update Firefox to ensure you’re benefiting from the latest performance improvements. Conclusion The behavior you’re experiencing is likely due to Firefox’s session restoration and memory management logic. Adjusting the settings mentioned above should help improve the situation. If the issue persists, feel free to provide additional details, such as your Firefox version and operating system, so I can assist you further. Thank you for your patience, and I hope this helps! P.S. (You can also read this Help article https://mzl.la/3vU7w5n) Best regards, Kaasplank3333