Hmmm, not sure, maybe not? I used the standard Windows method of creating a virtual drive, through the Disk Management utility.
It was definitely "detachable" using Windows terminology. Do I need to have it detached before launching BaseCamp, then with BaseCamp open, "mount" the virtual drive?
So, I've made progress, in that I've verified that if I copy files to an actual USB drive, it works. However, I'm still pursuing my preferred option, the virtual drive . At least this confirms that creating a virtual drive through the Windows Disk Management utility is the problem, as I suppose that's not recognized as removable, or a virtual USB drive.
Finally got it to work. There's software that will create a virtual drive recognized by Windows as removable media. The one I used is called ImDisk Virtual Disk Driver, which I found through the useful info that SUSSAMB shared. Please note this software is more of a utility than an app; also, its primary function is to mount existing virtual drives. It can create one, but depending the settings you choose, it typically sets up a temporary drive that only lives in memory - either physical memory (RAM) or virtual memory (pagefile.sys).
My solution was to create a VHD the normal Windows way (Disk Management utility), leave it empty (i.e. don't put your maps in there yet), mount it with ImDisk being sure to check the "Removable media" box (see screenshot below), and then copy the maps into the virtual drive after it's mounted.
ImDisk is a little tricky, hopefully the screenshot helps. The next thing I'll share is potentially helpful in two ways: (1) it can mount an existing virtual drive for you, instead of using the interface pictured above, and (2) once you're all set up properly and everything works, you'll still need to re-mount the virtual drive again if you restart your computer or if it otherwise becomes un-mounted. Since ImDisk has a bunch of command line functionality, you can create a command that mounts the virtual drive for you. Open a text file (Notepad or the like), drop in the following text:
imdisk -a -m #: -o rw,rem -f "D:\garmin maps.vhd"
then save the text file as a .cmd file instead of a .txt file (swap out "D:\garmin maps.vhd" for the path and file name of your virtual drive). As I alluded, you can then use this .cmd file to mount the virtual drive for you - the initial time or subsequent times or both. Please note that when you first mount the virtual drive, it may not work the first time. I've been playing around with this most of the day, and it's now a bit blurry, but I think it failed on me the first time. Perhaps restart your computer and try again if that happens to you. Also, it may prompt you to format the disk (virtual drive), even if you already did when you first created it. No worries, just let it do it again (NTFS or FAT32, it doesn't matter), then everything should be fine and ready to go. Recall, that we purposely left the virtual drive blank - it's only after you get it properly mounted for the first time that you then drop in your maps. You shouldn't have any issues with subsequent re-mounts... I haven't so far.
Please note this software is more of a utility than an app; also, its primary function is to mount existing virtual drives. It can create one, but depending the settings you choose, it typically sets up a temporary drive that only lives in memory - either physical memory (RAM) or virtual memory (pagefile.sys).
Imdisk has no problems creating a virtual disk using a file.
My solution was to create a VHD the normal Windows way (Disk Management utility), leave it empty (i.e. don't put your maps in there yet), mount it with ImDisk being sure to check the "Removable media" box (see screenshot below), and then copy the maps into the virtual drive after it's mounted.
Imdisk can do this itself. It installs a program for this in Control Panel (somewhat unusual).
The problem is that the ImDisk applet does not show up in Control Panel in "category" mode (you have to use one of "icon" modes).
You can create a desktop shortcut to the Control Panel icon by right clicking on it.
