I went update my charts and SD prompted me to allow an update of the software package. I clicked the appropriate permissions and just ended up with SD disappearing ! This happened twice and necessitated a system restore to get back to here. I have updated the charts, but retained my (apparently) earlier versuion of the software.

Why would this happen?

The computer is a Win7 netbook and this is the first time I've had difficulty with it when updating.

SD and a cheap Chinese satnav = Jobzagoodun.