Since migrating to exchange 2010 from exchange 2003 I have had some users complain that appointments vanish from their calendars. I also have users that used to be able to modify DL's and no get errors that they dont have permissions. Clients have office 2007 or 2010 and some mac clients on windows xp and windows 7Stonecold31666

Hi stonecold, Does just the appointments disappear, the meeting requests without the issue? Does the issue account use any other device to sync the emails item, such as mobile devices?. First of all, I would suggest that update the exchange 2010 to the latest version, and update the outlook 2007/2010 to the latest version. Some useful information about how to troubleshooting the kind issue, please refer to below: http://support.microsoft.com/default.aspx?scid=kb;EN-US;890436 Regards! Gavin TechNet Subscriber Support in forum If you have any feedback on our support, please contact tngfb@microsoft.com Please remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.

Yes they just disappear. The user in question do all have mobile devices, droid smart phones and ipads.Stonecold31666

Hi stonecold, I also have run into these kind issue many times, as usual, those maybe cause by the mobile devices, I would suggest that you could turn to help from the venders. I would make a test remove the mobile device which sync the emails from the exchange server. Regards! Gavin TechNet Subscriber Support in forum If you have any feedback on our support, please contact tngfb@microsoft.com Please remember to click “Mark as Answer” on the post that helps you, and to click “Unmark as Answer” if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.

Thank You. I am trying to narrow down the dates they went missing. Recently the CDO were updated on the system for blackberry to function and I have not heard of any going missing since then. Stonecold31666