I'm trying to migrate our domains mail from a IMAP server at Joyent to a new installation of Zimbra 5.0.9 with imapsync:

imapsync throws these errors at me:

+ NO msg #229 [zId1umXxCnAQQkF1gAjLcA:2927] in Archiv
+ Copying msg #229:2927 to folder Archiv
flags from : [\Answered \Seen $Joyent:id:123456 $NotJunk JunkRecorded]["10-Apr-2007 10:35:01 +0200"]
267 NO APPEND failed
at /usr/bin/imapsync line 1360
Couldn't append msg #229 (Subject:[RE: bla bla]) to folder Archiv: 267 NO APPEND failed

and in /opt/zimbra/log/mailbox.log I see the following errors:

2008-09-29 16:45:06,004 INFO [ImapServer-4] [name=xxx@xxx.tld;mid=4;ip=;] imap - APPEND failed: invalid name: $Joyent:id:123456

I'm out of ideas...