Disable caching on “Open additional mailboxes” for exchange account in Outlook

Office 2003 and prior does not cache external mail folders. Office 2007 caches external contacts and calendar only (not email) Office 2010 and beyond caches everything. This can be a problem if someone has a large archive mailbox and a small hard drive.

There are two solutions:

1. Disable shared folder caching. This will give the 2003 functionality ie. no caching of anything. Go to the exchange account properties, select “More settings”, then go to the advanced tab and uncheck “Download shared folders”
2. Disable shared folder email caching. This will give 2007 functionality – caching contacts and calendars, not email objects. Open regedit and navigate to the following key: HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Outlook\Cached Mode and set CacheOthersMail = 0