That's a common problem and easily fixed. With NTFS formatted drives you
need to allow indexing of the gpl folder. To do this open windows explorer
and browse to the sierra folder. Right-click on the gpl folder and select
properties, then click the advanced button. You'll see a check box to
allow indexing.
You don't need to enable the indexing service, and no, I have no idea why
it needs it either ;-)
Malc.