Puremessage and Inbox updating problem

Hi,

I have exchange 2013 in organization with Puremessage installed on the server. Domain users connect to domain using Outlook 2007/2010 clients. Last few days i'm experiencing strange problem.

Every morning when users open their outlook they get message at the bottom of the outlook saying "Updating inbox". Some of the mailboxes are quite large 10GB.  All old mails are already there, but it seems that outlook is re-downloading them again. Once updating is complete after exiting outlook and starting again the updating everything is OK and updating does not occur (ecxept for new emails ofcourse). But the next morning the process starts again.

I tried to remove outlook profile and delete manually .ost and other outlook files and then recreate profile, but that does't help.

I contacted Microsoft support and they suggested to turn off all PureMessage and Sophos services. I did that and after that the problem did not occur. So they concluded that the cause of the problem is PureMessage.

Any advice what might be the problem ?

Regards,

Josip