Firefox stored the bookmarks and history in a SQLite database named places.sqlite, so you need an older backup copy of places.sqlite to access the lost history. It is not easily possible to combine two of more history files as this requires to run specific SQLite queries (extract the moz_historyvisits table from one copy and insert it into another copy).

Most of the prefs you mention are no longer supported and likely have a trashcan, expiration.max_pages is a Number pref to set the maximum and is not a Boolean.

Firefox determines automatically how many pages can be kept without affecting performance. In current releases you can find this value if the click "Verify Integrity" on the "Help -> More Troubleshooting Information" (about:support) page.

• History can store a maximum of xxx unique pages

Previously this count was stored in places.history.expiration.transient_current_max_pages, but this is no longer used in 85+ (you can click the trashcan to reset/remove this pref).

You can create a new Number pref named places.history.expiration.max_pages if you want to override the automatically calculated number of pages (don't make its value too large).

Thank you. With the current options Firefox stores the History of only 7 days.

I followed your advice and the options now are as follows: places.history.expiration.max_pages false Is it correct? places.history.expiration.max_page 20000 This is new I have deleted: places.history.expiration.transient_current_max_pages 112348

And in summary, all options ('modified' only) with the search text "history" are: history true places.history.expiration.max_page 20000 places.history.expiration.max_pages false privacy.clearOnShutdown.history false privacy.history.custom true

Correct?

You may have security or cleanup software if you only keep history for a week, so check that first.

No, you can remove both prefs (i.e. click the trashcan) and only create this Number pref with plural pages. Paste places.history.expiration.max_pages in the search bar on about:config and select the Number radio button. You can set the value to 100000 or more (up to 999999) depending on how many sites you visit and how many visits you want to keep.

Sophos Home and Zonealarm pro are installed. Sometimes I run Spybot Search&Destroy. Any known conflicts?

Now I have only the following "history" prefs: history true places.history.expiration.max_pages 100000 privacy.clearOnShutdown.history false

According to support of Sophos this software should not cur the Firefox history. I have uninstalled Spybot S&D (hope there is nothing left) and try to contact Zanelabs.

Last option: new installation of Firefox? Can I keep my bookmarks?

Due to my experiences it would be a good new option in Firefox to make regular backups of user data that can be imported (cumulative if necessary) just in case. Especially because the handling of such data is not very normal-user-friendly (and safe).

See:

• https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles
• https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile

Sophos says NO and Zonelabs says NO to the question on possible impacts on Firefox history. In all communications there is the same "tenor": probably due to new Firefox versions. So PLEASE (to the developers) "restore" the clear option in the settings for the "History": Set the desired number of days for "Remember my browsing and download history. The internal calculation of something without tracability became a big "minus" for the software. As mmentioned: Backups easy to read (and modify) of important user data (like history) are absolutly essential for a new version. And as we already talk about new versions: There should be a complete downgrade option that works at least until the user "accepts" the new version. Perhaps this is not the rights forum for this general demands. So please if someone more familiar with the "Support" can forward them to the more appropriate place. This "improvement" of a new version (if the problem is really caused by it) took me and perhaps other users HOURS that would not be necessary. But thanks for the substantial answers. Martin

Finally with the following prefs (and uninstalled Spybot S&D?) Firefox now again keeps history for more then 7 days! history true places.history.expiration.max_pages 100000 privacy.clearOnShutdown.history false privacy.history.custom true

Thank you again!

And for my original question: "Is it possible to combine history/bookmark files?" I found a nice tool that combines history files: https://github.com/crazy-max/firefox-history-merger It worked fine for me.

Martin