Hi wanchoongchin-

I don't know why the URL is not valid. I would recommend going to the page you want to be your homepage, and re-setting the value like this:

• Firefox > Preferences > General > Home Page > Click 'Use Current Page' button

Hope that helps!

Someone else reported this error and the problem was that the old www.google.com/firefox page was set as home page. You can fix this by restoring the default Firefox home page using the "Restore to Default" button

Ref:

• /kb/latest-firefox-issues/discuss/2270 "url not valid" after firefox 9.0
• https://support.mozilla.org/en-US/kb/How%20to%20set%20the%20home%20page#w_restore-the-default-home-page

That issue can be caused by a corrupted or incomplete Visual C++ installation (multiple versions can be installed side-by-side; SxS) that is missing some runtime components (Redistributable Package) that Firefox depends on (problem with an embedded manifest file that specifies a specific runtime version).

You need to install the missing components (e.g. VisualC++ 2005 Redistrbutable).

• https://www.microsoft.com/download/en/details.aspx?id=5638

• [/questions/908165] The URL is not valid and cannot be loaded

• bug 713167 - Microsoft.VC80.CRT SideBySide errors, browsercomps.dll (fixed in Firefox 12)

I tried all of the ideas suggested here and none of them worked. Anyone have anything else?

Your problem is with the about:home page?

Start Firefox in Diagnose Firefox issues using Troubleshoot Mode to check if one of the extensions or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance/Themes).

• Don't make any changes on the Safe mode start window.
• https://support.mozilla.org/kb/Safe+Mode