https://support.mozilla.org/en-US/kb/update-firefox-latest-version?cache=no Did you update Firefox to the latest version '''66.0.1''' March 22, 2019

No, that isn't possible because in PB mode no data from PB mode windows and tabs is saved to the profile folder. That is how PB mode works and if Firefox cashes a lot the best is to avoid PB or regularly bookmark tabs or otherwise save session data. ---- If you have submitted crash reports then please post the IDs of one or more recent crash reports that start with "bp-". *bp-xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx You can find the report ID of recent crash reports on the "Help -> Troubleshooting Information" (about:support) page. *click the "All Crash Reports" button on this page to open the <b>about:crashes</b> page and see all crash reports. Alternatively you can open about:crashes via the location/address bar. See also: *https://support.mozilla.org/en-US/kb/Mozilla+Crash+Reporter