Under certain conditions, Exchange server users testing Outlook 2013 discovered that emptying the Deleted Items folder deleted everything in the mailbox.

Fix for this issue: Description of the Office Professional Plus 2013 Preview update: July 27, 2012 This update is for MSI-installed versions only (downloaded 700+ MB file). Click-to-run versions are updated automatically.

This is the result of using Online Exchange mode with one of the following conditions: using an ost while in online mode or group policy templates.

Cause 1: You have Outlook 2010 installed with an Exchange account in Online Mode, but with an .OST file associated with the profile (this can be the result of switching from Cached Mode at some point in the past). You install Outlook 2013 (upgrade or side-by-side) and use the Online Mode profile.

To avoid this problem, make sure your Outlook 2013 Exchange Account is configured for Cached Exchange Mode.

Cause 2: You have an Exchange Account configured in Online Mode and the "Cached Exchange Mode Sync Settings" administrative template policy setting is configured.

To remove the Cached Exchange Mode Sync Settings setting, open the Group Policy editor and change the Cached Exchange Mode Sync Settings policy to "Not Configured". This setting is under Microsoft Outlook 2013 > Account Settings > Cached Exchange Mode.

Download the Group Policy templates for Office 2013.

You can also edit the registry to remove the setting associated with the policy. Delete the syncwindowsetting value found in

HKEY_CURRENT_USER\Software\Microsoft\office\15.0\outlook\cached mode\syncwindowsetting

HKEY_CURRENT_USER\Software\Policies\Microsoft\office\15.0\outlook\cached mode\syncwindowsetting

To recover deleted items

Recover your data from the Exchange Dumpster, using Recover Deleted Items.

If you can’t recover your deleted items from the dumpster, you will need to contact your Exchange administrator to investigate the dumpster on the server.