Hi, Hoping someone here might be able to help. I've used NSIS to build an installer for an application. One part of it is to installer drivers for a USB device. Luckily some previous developer had written a script (Kuba Ober's InstallUpgradeDriver) to pretty much handle that aspect. As such it works great, but i've had a report of the driver instal failing with an error code of 5. This occurs from the system call to 'UpdateDriverForPlugAndPlayDevices' but unfortunatly i have no idea what this error refers to. I've posted on the NSIS forum, but haven't got any definitive answer there, so I'm hoping someone here might know the answer. The original author only added support for a single error code ; the masked value of ERROR_NO_SUCH_DEVINST is 523 !define ERROR_NO_SUCH_DEVINST -536870389 but there are others ERROR_FILE_NOT_FOUND ERROR_IN_WOW64 ERROR_INVALID_FLAGS NO_ERROR However I cannot find the error code for any of these (looked on msdn). From what I can tell I need the windows DDK, which I don't have and can't get. So anyone here happen to know what the error codes are for the 4 listed above (including NO_ERROR as it is an error really). Failing that any insight as to what error 5 when returned from 'UpdateDriverForPlugAndPlayDevices' means? Better yet are there any resources online where I could find out?