Windows 7 error “key not valid for use in specified state”

When you see that error upon trying to install or upgrade something on your Windows 7 64-bit machine, chances are that it is caused by a Windows Security update that you need to uninstall. There is probably no point in messing around with the registry or the application that you want to upgrade. Instead, remove the Windows update KB2918614 like this:

Open the control panel, then click  Windows Update

Windows 7 control panelClick Update History and then Installed (more...)