On 21.4.2012, at 11.01, Cor Bosman wrote: > prefix = Spam/ .. > quota2 = dict:Spam Quota::ns=spam:file:%h/spam-quota .. > Apr 21 10:00:11 lmtp1 dovecot: imap(cor): Error: quota: Unknown namespace: spam Oh. It would make more sense to have ns=spam, but unfortunately I hadn't thought of namespace names before v2.1. You need to use ns=Spam/