Hi ptales, HTML5 refers to a really wide range of built-in features, particularly around media players. Does the error message give you more information about what features it cannot access?

If you are getting the Mozilla Crash Reporter form, your Firefox may have logged some data that would help track down the cause of the problem. You can submit that data to Mozilla and share it with forum volunteers to see whether it points to the solution. Please check the support article "Firefox crashes - asking for support" for steps to get those crash report IDs from the about:crashes page, and then post some of the recent ones here.

Also and/or meanwhile, could you test in Firefox's Safe Mode? That temporarily deactivates extensions, hardware acceleration, and some other advanced features of Firefox that might make it more prone to crashing on some systems.

If Firefox is running: You can restart Firefox in Safe Mode using either:

• "3-bar" menu button > "?" button > Restart with Add-ons Disabled
• Help menu > Restart with Add-ons Disabled

and OK the restart.

If Firefox is not running: Hold down the Shift key when starting Firefox.

Both scenarios: A small dialog should appear. Click "Start in Safe Mode" (not Refresh).

Any less crashy?

This does not solve the problem.Firefox works fine,Just when I start the game it says that HTML5 is required to play the game.So when I am playing,it crashes during the game.So do I need to install HTML5 and where do I install from or activate.

It says browser does not support modem HTML5 features.It says please update or change your browser.

Hi ptales

Best is to leave a space after then period (.) that ends the sentence to prevent seeing this as an URL: game.So -> game. So and features.It -> features. It

You can try to set Flash to "Never Activate" via "about:addons -> Plugins" to prevent websites from detecting the plugin.

Thanks , But did not make a difference. Good idea though.

I registered for the game and went into the seemingly endless startup process. (I did not activate Flash.) Nothing crashed in the first 5 minutes with the hut, coins, field, trophy, but I got bored at the stilt house and closed the tab. Probably my village has been ransacked by now, but I digress.

Can you think of a way to replicate this problem if someone hasn't built up their city yet?

If you use extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) that can block content (Adblock Plus, NoScript, DuckDuckGo PE, Disconnect, Ghostery, Privacy Badger, uBlock Origin) always make sure such extensions do not block content.

• make sure your extensions and filters are updated to the latest version
• https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems

Firefox shows a purple shield instead of a gray shield at the left end of the location/address bar in case Enhanced Tracking Protection is blocking content. You can click shield icon for more detail and possibly disable the protection. You can check the Web Console for messages about blocked content.

• https://support.mozilla.org/en-US/kb/enhanced-tracking-protection-firefox-desktop
• https://support.mozilla.org/en-US/kb/trackers-and-scripts-firefox-blocks-enhanced-track

You can remove all data stored in Firefox for a specific domain via "Forget About This Site" in the right-click context menu of an history entry ("History -> Show All History" or "View -> Sidebar -> History").

Using "Forget About This Site" will remove all data stored in Firefox for this domain like history and cookies and passwords and exceptions and cache, so be cautious. If you have a password or other data for that domain that you do not want to lose then make sure to backup this data or make a note.

You can't recover from this 'forget' unless you have a backup of involved files.

If you revisit a 'forgotten' website then data for that website will be saved once again.

• https://support.mozilla.org/en-US/kb/delete-browsing-search-download-history-firefox