1. Click Start, click Run, type regedit in the Open box, and then click OK.
2. Locate and then click the following subkey in the registry: HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows
3. On the Edit menu, point to New, and then click New Key and name the key Windows Search.
4. Click on the new key Windows Search.
5. On the Edit menu, point to New, and then click DWORD Value.
6. Type PreventIndexingOutlook for the name of the DWORD, and then press Enter.
7. Right-click PreventIndexingOutlook, and then click Modify.
8. In the Value data box, type 1 to enable the registry entry, and then click OK.
9. Note to disable the PreventIndexingOutlook setting, type 0 (zero), and then click OK.
10. Exit Registry Editor, and then restart Outlook.