Value data: 1
This registry value may trigger the issue when Outlook is using a Cached Exchange Mode profile.
Important Follow the steps in this section carefully. Serious problems might occur if you modify the registry incorrectly. Before you modify it, back up the registry for restoration in case problems occur.
- Exit Outlook.
- Start Registry Editor. To do this, use one of the following methods, as appropriate for your version of Windows:
- Windows 8: Press Windows Key + R to open a Run dialog box. Type regedit.exe, and then click OK.
- Windows 7: Click Start, type regedit.exe in the search box, and then press Enter.
- In Registry Editor, locate the following subkey in the registry:HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Outlook\PST
- Locate and right-click the following value:UseLegacyCacheSize
- Click Delete, and then click Yes to confirm the deletion.
- Exit Registry Editor.
The operation failed. The messaging interfaces have returned an unknown error. If the problem persists, restart Outlook.
- In Control Panel, open the Administrative Tools item.
- Double-click Event Viewer.
- In the navigation pane, select Microsoft Office Alerts under Applications and Services Logs.
Article ID: 3096065 - Last Review: 22 Sep 2015 - Revision: 1