This does not come with any version of Firefox install or as an update from Mozilla.

Perhaps this is being installed by one of your Extensions you have installed in Firefox or by a external software you have installed or updated recently.

https://support.mozilla.org/en-US/kb/what-search-hijacking https://support.mozilla.org/en-US/kb/remove-toolbar-has-taken-over-your-firefox-search https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-caused-malware

Thanks for your reply James. If anyone has any specific information and steps to take to prevent this PUP being installed, I'd appreciate it.

All of the extensions I have are reasonably trustworthy and I would like to try to track down and block startpage from reinstalled.

I am aware of four ways to add a search engine to Firefox:

(1) An extension (2) Manually adding the search engine from the address bar of the search site (Autodiscovery) (3) Enterprise policy (https://mozilla.github.io/policy-templates/#searchengines--add) (4) The undocumented "browser.urlbar.update2.engineAliasRefresh" preference which adds a form to manually create a new search engine from the Settings page.

Since you trust your extensions not to be doing this, I'll skip #1 and mention how to investigate #3:

In the address bar, type or paste about:policies and press Enter to load the About Policies page. Normally, the "Active" panel just says "The Enterprise Policies service is inactive." Does yours list any active search policies?

Thanks It says :|Policy name- Certificates / Policy Value - ImportEnterpriseRoots / true

That policy sets Firefox to trust security certificate added to the Windows system certificate store, so that's not related.

Circling back to what happens at startup, which of these are you seeing (certainly it could be more than one):

(1) Your home page is changed to Startpage.com -- this is the page that appears when you press Ctrl+N to open a new window (How to set the home page)

(2) Startpage.com appears at startup, but not in new windows, only in the active window

(3) Startpage.com appears in every new tab (Ctrl+T)

(4) Startpage.com is added as a search engine BUT it is NOT made the default search engine, it's just one of the icons along the bottom of the autocomplete drop-down when entering a query in the address bar

(5) Startpage.com is added as a search engine AND it is made the default search engine -- when you are typing in the address bar, the top line of the drop-down says Firefox will search with Startpage

Or is it some site other than Startpage.com itself that is misusing its name?