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