Open-Xchange OXtender 2 issues with Outlook mail sync, some mails missing on the client

I use the Open-Xchange OXtender 2 to sync my groupware account with Outlook 2013  client at work.

The Open-Xchange Server Version is 7.2.2-Rev 14, The OXtender 2 Version is 7.0.64.2861 (32 bit). My OS is Windows 8 (64 bit) with Office 2013 (32 bit).

A few days ago i realized, that some mails in my server inbox did not appear in the Outlook inbox, but neither the mail content nor the OXtender logs gave me helpful information why it happened to this particular mails.

So i decided to "reset" the OXtender local cache as described here: (Be careful! All your local data is lost! Backup first in case not all the data is on the server!)

Use the SupportTool to re-create OXtender 2 MAPI services
http://oxpedia.org/wiki/index.php?title=Outlook_OXtender_2_Recreate_Service

I found the support tool on my computer here:
C:\Program Files (x86)\Open-Xchange\OXtender 2 for Microsoft Outlook\Profile

This is how it looks like:

After re-creating the service, the sync was working fine again.