Having relocated my virtual folders to a new namespace - I'm having some subscription challenges.  I'm able to reach them via telnet without issue - and some clients have better luck than others.  Some folders have no problems at all - some seem different.

In trying to identify what might be the issue - at the moment the only thing I'm seeing is the ones that are completely without issue don't have any "weird" flags.

Example: an apparently "clean" virtual folder:

. select virtual/Flagged

• OK [CLOSED] Previous mailbox closed.
• FLAGS (\Answered \Flagged \Deleted \Seen \Draft $Forwarded)
• OK [PERMANENTFLAGS (\Answered \Flagged \Deleted \Seen \Draft $Forwarded \*)] Flags permitted.
• 12 EXISTS
• 0 RECENT
• OK [UNSEEN 7] First unseen.
• OK [UIDVALIDITY 1535841027] UIDs valid
• OK [UIDNEXT 13] Predicted next UID
• OK [HIGHESTMODSEQ 3] Highest . OK [READ-WRITE] Select completed (0.316 + 0.000 + 0.315 secs).

This folder is recognized by all clients.  But this one:

. select virtual/INBOX

• OK [CLOSED] Previous mailbox closed.
• FLAGS (\Answered \Flagged \Deleted \Seen \Draft $Forwarded junk $MDNSent)
• OK [PERMANENTFLAGS (\Answered \Flagged \Deleted \Seen \Draft $Forwarded junk $MDNSent \*)] Flags permitted.
• 9540 EXISTS
• 0 RECENT
• OK [UNSEEN 85] First unseen.
• OK [UIDVALIDITY 1535841672] UIDs valid
• OK [UIDNEXT 9541] Predicted next UID . OK [READ-WRITE] Select completed (44.266 + 0.000 + 44.265 secs).

Is a little more troublesome.  And then...

. select virtual/Archives

• FLAGS (\Answered \Flagged \Deleted \Seen \Draft $MDNSent unknown-0 unknown-2 unknown-3 unknown-5 unknown-9 unknown-4 $Forwarded unknown-7 unknown-8 junk $NotJunk $label5)
• OK [PERMANENTFLAGS (\Answered \Flagged \Deleted \Seen \Draft $MDNSent unknown-0 unknown-2 unknown-3 unknown-5 unknown-9 unknown-4 $Forwarded unknown-7 unknown-8 junk $NotJunk $label5 \*)] Flags permitted.
• 142605 EXISTS
• 0 RECENT
• OK [UNSEEN 82998] First unseen.
• OK [UIDVALIDITY 1535841824] UIDs valid
• OK [UIDNEXT 142606] Predicted next UID . OK [READ-WRITE] Select completed (10.217 + 0.000 + 10.217 secs).

I can't get Thunderbird to recognize it all (though RoundCube web client works).

There very well may be something totally separate from the flags that's causing the problem, but, is there a way to strip the flags off?  I tried:

doveadm flags remove -u <username> '$MDNSent unknown-0 unknown-2 unknown-3 unknown-5 unknown-9 unknown-4 unknown-7 unknown-8 junk $NotJunk $label5' mailbox 'inbox/Archive/2004'

since that's one of the source folders of the virtual folder - no error, but no apparent change.  Same for operating on the virtual folder directly.

-- Daniel