Hello dixxy_0512,
No one can help if you don't provide at least a modicum of informatiºn.
What is the exact error messªge?
Are you running WU/MU automatic/manual, ? O/S is what?
What build of Windows Defender are you on?
Just for the record. What version are you now showing? Mine indicates
Windows Defender Version: 1.1.1593.0
Engine Version: 1.1.1904.0
Definition Version: 1.14.1950.9
Does that check out with you?
Is this occuring in a corporate environment or on a home system/network?
Is this a home machine, or one used in an office?
Since you haven't told us anything about your computer, operating system,
antivirus, etc. all I can suggest is that you go through the preparatory
work here:
http://support.microsoft.com/kb/555375