If that is the case couldn't you pretty much remove the duplicate letter from happening by assign drive letters to your archive drives starting at Z and moving forward.
I actually assign
all of my external hard drives as drive X (via the
awesome USBDLM application), which exacerbates the problem with MC. Since they're always drive X, the files from all of the other drives are always "broken" whenever I plug in
one of the drives.
However, using Drive X for all of my external drives is convenient for LOTS of reasons. The biggest one is just that there aren't enough drive letters in the alphabet.
On my server, I have these permanently mounted drives right now:
C (system and most applications)
D (optical)
E (optical)
F (USB optical duplicator)
M (media RAID)
N (a temporary work space drive used for compression and video editing)
P (my "portable" backup of drive M)
R (my Acronis recovery backup drive)
S (my "secure documents" USB flash drive, which backs up my most critical documents that live in a TrueCrypt container on my U drive)
T (my TV recording drive)
U (my users drive with My Documents and additional apps, since my C drive is a relatively small SSD)
V (my virtual optical drive from Daemon Tools)
W (my "work" RAID, with my professional video work stuff)
Plus, I have one of those 7-in-one media card readers in my PC, which uses drives G, H, I, and J.
So, that's 17 of a possible 26 drive letters used right off the bat. Then, you have A and B which Windows still thinks are reserved for floppy drives even though no one has those permanently attached (or at all) anymore. I've hit problems in the past with some applications if you try to use those letters for real drives or network drives, so it is best to not use them.
So, that leaves me with 7 possible drive letters left.
Already, I have these external disks on my shelf or in my bag that I use fairly regularly.
1. archive01-tv (2TB WD Green) - full
2. archive02-movies (2TB WD Green) - full
3. archive03-tv (1.5TB WD Green) - 50% fullish
4. archive04-movies (2TB WD Green) - 10% fullish
5. system_images (2.5TB Seagate) - used for drive images of all of my systems
6. VM_drive (2TB WD Black) - contains a FreeDOS VM, Ubuntu VM, Win98SE VM, two different Win7 VMs, and a Snow Leopard VM
7. portable_edit (2TB WD Black) - I use this drive to bring work home from the office where my video sources are stored on a 6TB RAID and a variety of SAN shares.
And, I have a smattering of USB flash drives of course, including some that are bootable with system utilities, recovery things for Acronis, virus fighting tools, and just "sneakernet" files. Oh, and the aforementioned TrueCrypt container with my financial records, which needs to be able to be mounted as a drive letter by TrueCrypt when I want to use the contents.
Now, I never need to connect all of those drives at once, but how could I manually assign all of those disks a drive letter and be sure that they'd never overlap when I plug in a random USB flash drive from a friend? Plus, keeping track of them all (wait, is this one supposed to be drive X or Q) and making sure that all of my different machines use the same drive letters for the same drives would be a huge pain in the butt. For example, when I want to play one of those files off of my archive03-tv drive (like an episode of Boardwalk Empire from last season) on the HTPC, I go to the shelf, pull the proper drive, and plug it into my drive dock attached to the HTPC. MC plays the file. When I want to play it on my laptop, I plug it into the Laptop's drive dock. If that drive was drive Q, I'd have to manually go to each of my individual machines one at a time with each drive and plug them in and manually change the drive letter (and then what about if I need to reinstall Windows somewhere)... Yeah, that's not going to happen. I have 4 different machines I use these on regularly. That's a whole lot of plugging!
And, of course, I'm out of letters. So now my only choice is to use clunky named volumes for the drives which don't work with lots of older and stupider applications. Or, you know, never run out of space again.
So, instead, I use USBDLM to automatically assign all of those numbered "external" drives above as Drive X. This is easy to do. USBDLM has lots of ways to detect a drive and permanently assign a particular drive letter to the drive, and it is configured with a simple INI file which I can easily copy around to my other machines (in fact, I store the INI file in Dropbox so I can always get to the latest version if I need it).
Now, I understand that I'm an extreme case. Most people aren't going to have that many. However, most people ALSO aren't going to want to be bothered to keep track of it all, and to use a third-party utility like USBDLM. I bet most people would just plug it in and let Windows assign whatever it wants to (probably E or something) and then use that. Since they don't change their drives around much, it probably "just works" for a long while. Until that fateful day that they have the external drive unplugged (maybe they don't have enough USB ports on a laptop) and they plug in a camera card reader that assigns E, F, G, and H. Once you do that, if you have MC open, and you plug a SD card or Compact Flash card into the wrong slot on the reader, suddenly MC removes every single file on the drive E drive from their entire library if they have the default configuration of MC enabled.
This is
not a good plan.
MC is catering to HTPC and video users now. We have lots of videos, or else we wouldn't be using MC to manage them. Videos are big. External hard drives are big and cheap (or they were until the flood, but they will be again).
It isn't that unusual that someone might have 2 or 3 drives they want to use, but not keep connected all the time. I can't imagine that I'm the only one who wants to hang onto last years season of Game of Thrones, but doesn't want it sucking up (expensive) space on my main online media RAID volume?
Relying on the user to manage arcane and confusing drive letters manually starting with the "highest letter" (fighting windows) isn't a real solution.