Firefox normally tries to restore your previous session windows and tabs after a crash. You can set Firefox to instead show you a list of the windows and tabs in the session so you can select only the ones you want back. Here's how:

(i) In a new tab, type or paste about:config in the address bar and press Enter/Return. Click the button promising to be careful.

(ii) In the search box above the list, type or paste sess and pause while the list is filtered

(iii) Double-click the browser.sessionstore.max_resumed_crashes preference and change the value from 1 to 0 (that's a zero) and click OK

Please do not change any other sessionstore preferences without researching or asking about them first.

Hope this helps.

I guess that is the apology page you mentioned eventually getting. Now you'll get that on the first try.

If it's like the fake FBI/Interpol browser lock page, This add-on can stop such pages; https://addons.mozilla.org/en-US/firefox/addon/disallow-script-button/ disallow Script Button

The Disallow Script button looks like a letter "M" and the title is the Minus Script, drag and drop the button on a toolbar. If the button is not displayed then nothing operates, except rules for plugins.

Another way out of the trap is to (force it if needed) Close Firefox. Wait about 20 seconds for Firefox to finish closing. Right-click on the Firefox icon and select Open New Window.

Sometimes this works. If it opens, close it by Menu > File > Exit. This will flush out that web page from the Session Store.