It's possible to reserve a drive letter for each drive used.
This is exactly what I do, and what I intended to write about. I always assigns drives as follows:
C: Windows and Program Files drive
D: My Documents, Backup and pagefile.sys drive
E:-N: External and/or other internal mass storage drives
P:-T: USB stick drives
U:-Z: Optical and/or virtual drives.
Disc Management console does this job perfectly for me.
What I concluded was that you either used automatic assigning first available drive letter, or you purposely assigned same letter. If first, then you should reserve drive letter for each external HDD, and if second, you have a problem when both attached at the same time - one of them wouldn't recognized by Windows.
It's possible to reserve a drive letter for each drive used.
Yes - I can force pvd to recognise movies have changed path, but the change path scan does not update "media label field" which I would like to use to know which HD a particular movie is on.
Now, I'm confused again. If you reserve different letter for each drive, it implies path changing, so scanning as I described earlier overwrites Media label field? But, this was rather rhetorical, you don't have to reply on this.