Same as on USB-devices some time ago: A TrueCrypt container that is just only shown (no access) in a DO-lister can't be unmounted (only force). When changing to another folder/drive it unmounts without problems, so DO locks the device (container).
Opus monitors the displayed volume for changes (which I think requires a lock) and may also set the window's current directory to the folder it shows (or at least does when commands are launched, by default).
I think there is a "I'd like to eject, please let go of me" type of message which TrueCrypt (and other devices) can send. Are you proposing that Opus should respond to that by changing to another volume (or My Computer, or similar) so that it can be released?
Hello, sorry for delay (lot of work).
If DO would switch automatically to desktop or somewhere else this would be great. I always forget to switch or close the lister with an error message as a result.
I don't understand why I'm able to unmount an opened DaemonTools-Drive without any problems, but TC not.
I think when I was investigating this before I found that TrueCrypt simply doesn't send the "dismount request" message that removable drives are meant to send. Therefore Opus never knows it wants to dismount and so doesn't release the lock.
I read that TrueCrypt used not to, but in more recent versions it does broadcast a window message to say it's dismounting a drive.
I think I saw something about that when reading about the bug in TortoiseSVN where the Tortoise cache process locks folders forever (which it still does, sigh).
Perhaps TrueCrypt doesn't broadcast it reliably, which might explain some of the issues I see with Tortoise locking drives (although some of them are definitely bugs in Tortoise since it keeps random folders locked for hours).
I'll add a command to my unmount button that will change the listers' dir (unfortunately I have to change both listers in dual mode).