clean up outlook 2010 cache

Turn Off Cached Exchange Mode

Click the Start Menu > Control Panel > Mail
Click the button labeled Show Profiles
Highlight the profile you are using for Exchange email
Click the Properties button.
Click the Email Accounts button
Highlight the Microsoft Exchange account and click the Change button.
Uncheck the box that says “Use Cached Exchange Mode”
Click the Next button
Click Finish.


Delete OST files from hard drive

Windows 7: C:\Users\username\AppData\Local\Microsoft\Outlook
Windows Vista: C:\User\user name\Local Settings\Application Data\Microsoft\Outlook
Windows XP: C:\Documents and Settings\user\Local Settings\Application Data\Microsoft\Outlook


Turn On Cached Exchange Mode

Click the Start Menu > Control Panel > Mail
Click the button labeled Show Profiles
Highlight the profile you are using for Exchange email
Click the Properties button.
Click the Email Accounts button
Highlight the Microsoft Exchange account and click the Change button.
Check the box that says “Use Cached Exchange Mode”
Click the Next button
Click Finish.
Restart Outlook


Once Outlook is restarted, all of your mailbox data  including email, calendars, tasks and notes will download to your computer again.  This process may take a while to complete depending on the size of your mailbox.  You can watch the progress in the lower right corner of the Outlook application window.