Some of the sins of the RTM version of Windows Vista have not been exorcised with the advent of Service Pack 1. The gold Build of Vista was plagued from the get go with hardware incompatibility problems, mainly due to the lack of compatible drivers. However, while incompatible drivers can be blamed on hardware developers in addition to the poor Microsoft evangelism efforts, there are occasions when it's actually the fault of Windows Vista. Both the RTM and SP1 variants of the latest Windows client as well as Windows Server 2008 have problems when it comes down to correctly identifying digitally signed drivers.

"On a computer that is running Windows Vista or Windows Server 2008, you open Device Manager to review the properties of a driver. However, the Digital Signer field on the Driver tab displays the following status message: 'Not digitally signed'. This behavior occurs even though the driver is digitally signed," Microsoft revealed.

The Redmond company indicated that a solution is available for the problem. However, Microsoft did not deliver an update, but just a hotfix, and as such, end users coming across this issue will have to contact the software giant directly in order access a resolve.

"This problem occurs because Device Manager verifies the digital signing information by using the class GUID of the previous driver and the driver name of the current driver. Because no driver is found to match the old class GUID, Device Manager detects the driver as an unsigned driver," the software company explained.

According to official data made available by the Redmond giant, Windows Vista, following the introduction of Service Pack 1, is compatible with in excess of 5,500 hardware products. However, this does not mean that the operating system will not continue experiencing driver issues, despite Microsoft's best efforts in this regard.