IDLE error

[D CATALIN BADIRCA]

Hi,

I’ve installed a Postfix with Cyrus IMAP and Cyrus SASL. All good, can send/receive email very fast.
There is one error in the logs that I cannot understand what impact has on the mail system. I’ve tried searching books,documentations, mail lists, google and nothing helped me. Maybe some of you gurus will help me understand.
Here is the error I have in the log:

imaps[9717]: IDLE: error sending message INIT to idled for mailbox user.test: No such file or directory. Falling back to polling every 60 seconds.


I have Thunderbird as a MUA and each time I press the Get Messages button I get this error, but not always. 

Thank you !
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