Recently closed tabs and windows are empty after restart
While I'm using FF the Recently closed tabs and Recently closed windows lists (see under History) get populated, but after I restart they're empty. I turned on "Restore session" and it did restore my previous window, but even then the Recently closed tabs and windows were empty. I'm not aware of having changed anything except I cleared cache this morning after a problem with GMail. I'm assuming this isn't intended functionality?
Wšykne wótegrona (1)
There are other things that need attention. The System Details list shows that you have an outdated Flash plugin, current is 32.0.0.207 (32.0 r0;2019/06/11).
- Shockwave Flash 10.2 r153
- Shockwave Flash 32.0 r0
You can find the location of a plugin on the about:plugins page and in the pluginreg.dat file in the Firefox profile folder.
You can download the latest NPAPI Flash plugin for Firefox on this page.
Make sure to remove checkmarks for including unwanted additional software.
"Recently Closed Tabs/Windows" are stored as part of session data. You wrote that Restore Previous Session worked to restore the windows in this session and that indicates that sessionstore is working properly. This wouldn't work if you would use "Clear history when Firefox closes" to clear the browsing history.
Is "Clear history when Firefox closes" enabled to clear any data if you check its settings?
Start Firefox in Safe Mode to check if one of the extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) or if hardware acceleration is is causing the problem.
- switch to the DEFAULT theme: "3-bar" menu button or Tools -> Add-ons -> Themes
- do NOT click the "Refresh Firefox" button on the Safe Mode start window