[glorgau]

Then just disconnect drive B during the "interrogation"and downloading on drive A.

This supposes that nothing is happening in the background while the B drive is connected. It could be sitting there doing a scan every X minutes and storing that to Drive A. In fact, it probably is.

[PissAndVinegar]

Actually the problem is that pesky old registry.

The registry essentially keeps a log of all the software you have installed whether it's on C: or Z:....