1. From the Start menu, type regedit.exe in the search box, and then press Enter.If you are prompted for an administrator password or for confirmation, type the password or provide confirmation.
2. In Registry Editor, navigate to: HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main\FeatureControl\FEATURE_BROWSER_EMULATION
3. Find the REG_DWORD OUTLOOK.EXE and double-click to edit.
4. Select Decimal and change it to 11001 and select OK.
5. Close Registry Editor and restart Outlook.