Hello, I'm on a Windows 2008 server R2 and I have to make a virtual server of it for testing the update of plesk panel from 10.0.1 to 10.3.1 (I did the update step by step also 10.0.1 to 10.1.1 ...) and I have an error : Installation started in background Determining the packages that need to be installed. File downloading PANEL-WIN_10.1.1/dist-msi-Microsoft-2003-i386/panel.msi: completed. File downloading PANEL-WIN_10.1.1/dist-msi-Microsoft-2003-i386/plesk-skins.msi: completed. File downloading PANEL-WIN_10.1.1/dist-msi-Microsoft-2003-i386/plesk-backup.msi: completed. File downloading PANEL-WIN_10.1.1/dist-msi-Microsoft-2003-i386/php5.msi:completed. File downloading PANEL-WIN_10.1.1/dist-msi-Microsoft-2003-i386/webmail.msi: completed. File downloading SITEBUILDER-WIN_5.1.0/dist-msi-Microsoft-2003-i386/sitebuilder.msi: completed. File downloading BILLING-WIN_10.1.0/dist-msi-Microsoft-2003-i386/billing.msi: completed. File downloading BILLING-WIN_10.1.0/dist-msi-Microsoft-2003-i386/billing-plugins.msi: completed. Starting installation of packages upgrading Parallels Panel... MSI: Error! The installer has encountered an unexpected error installing this package. This may indicate a problem with this package. The error code is 2318. Failed to install 'C:\2a6894ae4cbfca547be353e4cd72a29d\parallels\PANEL-WIN_10.1.1\dist-msi-Microsoft-2003-i386\panel.msi' with error 1603 I have search 1-2 days and I haven't found any solution. I have test to restart the update, to repair the installation, to check the permissions, but nothing resolve it... Please anybody can help me ?