[MlMt] sync bug

[Bill Cole]

On 18 Nov 2019, at 13:44, Alain Israel wrote:

> This weekend when I launched Mailmate, I got the following warning 
> (attached). All my mailboxes (and I have a great number) got 
> desynchronized, and take forever (and even more) to resynchronize (and 
> I suspect I will get the same problem the next time I launch 
> Mailmate).

Probably not.

UIDVALIDITY is a tag used by an IMAP server to alert clients when the 
UID values for messages in a mailbox may have changed. Nothing a client 
like MM does can cause a mailbox's UIDVALIDITY value to change and when 
that value changes there is no reliable strategy for a client other than 
to fully resynch the mailbox.

The most common reason for UIDVALIDITY to change is if a server has had 
some sort of failure that required a rebuild of mailboxes. For Exchange 
servers, it also is rumored to happen whenever the mail admin sneezes.

> What is the best solution to solve the problem? Reinstall Mailmate? 
> Anything else?

No, do not reinstall MailMate. MailMate didn't cause this and cannot 
prevent it.

> My other mail clients seem to work OK.
>
> Importantly, the same problem happened when I opened Mailmate on 2 
> different computers.

Any IMAP client that maintains a persistent local cache of messages MUST 
invalidate that cache when the UIDVALIDITY value of a mailbox changes 
from what the client last saw. Some clients do not maintain such a cache 
and many that do won't bother alerting the user when they need to do a 
full resynch.


-- 
Bill Cole
bill at scconsult.com or billcole at apache.org
(AKA @grumpybozo and many *@billmail.scconsult.com addresses)
Not Currently Available For Hire