[Dovecot] unable to lock for exclusive access: Resource temporarily unavailable

npap at ecs.gr npap at ecs.gr
Wed Sep 25 12:17:47 EEST 2013

Could you please provide more information about what you mean with  
Maildir format? I am not so familiar.
Is it a quick and stable solution?

Best Regards,


Quoting Timo Sirainen <tss at iki.fi>:

> On 25.9.2013, at 10.27, Nikos Papadopoulos <npap at ecs.gr> wrote:
>> We have a mail server (RHEL 6.0, Postfix and Dovecot 1.0.7).
>> mail_location: mbox:~/mail:INBOX=/var/mail/%u
>> There is great delay in the delivery of the emails. Some seem to not be
>> delivered at all. Issuing the mailq command we get the following message for
>> almost all the email accounts:
>> (cannot update mailbox /var/mail/xyz for user xyz. unable to lock for
>> exclusive access: Resource temporarily unavailable)
> mbox format is problematic in this way. Newer Dovecot versions  
> (v2.x) do some extra work to unlock the mbox earlier with POP3. That  
> might help you. Or you could switch to Maildir format where this  
> isn't a problem. I'm not sure why it started happening only now and  
> not earlier. Perhaps the POP3 clients are downloading mails more  
> slowly, perhaps you're getting more mail and things are running  
> slower than before.

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