>Designer complaining! Oh well I didn't use designer and UInt64 compiled w/o errors.

Presently, this is defined as follow:

        Public nAvailableByte As Double = 0
        Public nFreeSpace As Double = 0
        Public nFreeSpaceToCaller As Double = 0

I do not have any error nor any warning at the designer level. However, if I change all those three lines to Int64, GetDiskFreeSpaceEx() complains that:

Implicit conversion from 'Double' to 'Long' in copying the value of 'ByRef' parameter 'lpTotalNumberOfBytes' back to the matching argument.

I see also that the GetDiskFreeSpaceEx() line does require a double. This is what the intellisense is showing. So, it seems that everything is properly defined. The problem seems to reside somewhere else.