Click on the Start button and select Command Prompt (Admin). (You'll need to click Yes to allow it to make changes to the computer.)
When the Command Prompt appears, type (or paste) sfc /scannow then hit Enter (there is a space between sfc and /).
Once System File Checker is finished, reboot the computer.
Users are reporting that System File Checker reports corruption in mlang.dlI.Mui and Windows.Media.Speech.UXRes.dll.mui. SFC replaces the files and after a reboot, Outlook works again.