Open an email that's signed, Now you will receive a different message:.Value: maafgiompdekodanheihhgilkjchcakm meCrxUpdate.ashx.User Configuration-> Administrative Templates-> Google-> Google Chrome-> Extensions-> Configure the list of force-installed apps and extensions.Value: maafgiompdekodanheihhgilkjchcakm.Reg Key: HKEY_CURRENT_USER\Software\Policies\Google\Chrome\ExtensionInstallForcelist.You must force Chrome to allow you to install this extension install either by Registry key or Policy.Please contact your IT administrator for help installing the extension.' This message has a digital signature, but it wasn't verified because the S/MIME extension isn't installed. 'The digital signature on this message can't be verified.Open an email that's signed, there will be a message informing you that you do not have S/MIME extension installed but not offering a link to install the extension (see below):.