[Dovecot] Problems with masteruser

I have very strange problem with masteruser. See two logs below:

# telnet localhost 143 Trying 127.0.0.1... Connected to localhost. Escape character is '^]'.

• OK [CAPABILITY IMAP4rev1 LITERAL+ SASL-IR LOGIN-REFERRALS ID ENABLE STARTTLS AUTH=PLAIN AUTH=LOGIN] Welcome to our post server! x login nevorotin password x OK [CAPABILITY IMAP4rev1 LITERAL+ SASL-IR LOGIN-REFERRALS ID ENABLE SORT SORT=DISPLAY THREAD=REFERENCES THREAD=REFS MULTIAPPEND UNSELECT IDLE CHILDREN NAMESPACE UIDPLUS LIST-EXTENDED I18NLEVEL=1 CONDSTORE QRESYNC ESEARCH ESORT SEARCHRES WITHIN CONTEXT=SEARCH LIST-STATUS ACL RIGHTS=texk] Logged in x list "" "*"
• LIST (\HasNoChildren) "/" "INBOX" x OK List completed. x getacl INBOX
• ACL "INBOX" "nevorotin" lrwstipekxacd x OK Getacl completed.

All work perfectly. And then I log in throw masteruser:

# telnet localhost 143 Trying 127.0.0.1... Connected to localhost. Escape character is '^]'.

• OK [CAPABILITY IMAP4rev1 LITERAL+ SASL-IR LOGIN-REFERRALS ID ENABLE STARTTLS AUTH=PLAIN AUTH=LOGIN] Welcome to our post server! x login nevorotin*master masterpassword x OK [CAPABILITY IMAP4rev1 LITERAL+ SASL-IR LOGIN-REFERRALS ID ENABLE SORT SORT=DISPLAY THREAD=REFERENCES THREAD=REFS MULTIAPPEND UNSELECT IDLE CHILDREN NAMESPACE UIDPLUS LIST-EXTENDED I18NLEVEL=1 CONDSTORE QRESYNC ESEARCH ESORT SEARCHRES WITHIN CONTEXT=SEARCH LIST-STATUS ACL RIGHTS=texk] Logged in x list "" "*"
• LIST (\Unmarked) "/" "INBOX" x OK List completed. x getacl INBOX x NO [NONEXISTENT] Mailbox doesn't exist: INBOX

I've turned on debug logging, but there aren't any errors. I only see that masteruser succesfully logged in as nevorotin. How can I make a masteruser login to user account exactly the same as simple user login? Now it don't work at all [?]

I use 1.2.10 version of dovecot.