[Dovecot] Error "Initializing mail storage ..." after upgrading to 2.2.10

[Charles Marcus]

On 2/27/2014 3:48 AM, Götz Reinicke - IT Koordinator 
<goetz.reinicke at filmakademie.de> wrote:
> Am 27.02.14 09:41, schrieb Steffen Kaiser:
>> On Thu, 27 Feb 2014, Götz Reinicke - IT Koordinator wrote:
>>> But on one mailbox I do get an error:
>>> Error: user rechnnugseingang-animationsinstitut: Initialization failed:
>>> Initializing mail storage from mail_location setting failed
>>> Error: Invalid user settings. Refer to server log for more information.
>> Is above error the only error in the log?

> Yes, thats the only log for about 8 hours +- now.

>>> There is a homedirectory and the permissions are set like on all other
>>> accounts.
>>> The username is quite long (35 characters) but an other one with 34 is
>>> working fine.

>> I do not have such long names ...
>>
>> I suggest to turn on mail_debug, then you see all paths a.s.o.

> Switched it on, but there are no more error messages.

doveconf -n output?

(should have provided that in the first email)