My reading of http://kb.mozillazine.org/Command_line_arguments_-_Thunderbird indicates that the URI must be for a specific email, not a folder. The Current part looks more like a maildir location that an individual mail.

Thanks for the reply. Yes, this was my initial reading, but being a bit desperate for this feature, I just tried it, and it seems to be working flawlessly for folders without a space in them, at least for IMAP. So I wondered if I'm missing a trick with escaping the space character.

Is there any better solutions for this? Perhaps somebody knows a plugin? Maybe running thunderbird in marionette mode may be an option, but I haven't seen much documentation/examples for this. I'd be very grateful for any pointers.

There are lots of suggestions online for escaping spaces on Linux. One is to insert \ before a space, e.g.

00\ Current

Thanks for your reply. Yes, I tried all possibilities that I could think of: %20, backslash in front of space, replacing by underscore, etc. but unfortunately, nothing seemed to work.