Definition Update for Windows Defender fails

When I run Windows update I am always getting the message below. the Definition number changes as a new definition is released.

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There were problems installing some updates, but we'll try again later. If you keep seeing this and want to search the web or contact support for information, this may help:
Definition Update for Windows Defender - KB2267602 (Definition 1.239.713.0) - Error 0x80070643
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I started getting the message on Windows 10 AU about 4 days ago. It appears the definitions are being downloaded but the install fails. I decided to install the Windows 10 Creators Update yesterday. I did a clean install. After the initial install I was able to install definitions. However, somewhere along the line it started to fail again. On AU I could update Winders Defender by doing it within Winders Defender itself. Under CU it also fails within Windows Defender, which has been totally revamped, so it looks like no more definition updates for now. It appears I am stuck at KB2267602 (Definition 1.239.603.0)

Is there a fix for this? Again let me repeat. I had this problem on Windows 10 AU starting about 4 days ago so it's not limited to Windows 10 CU.

Just to say, I've been experiencing the exact same thing since the latter half of last week.

(I've tried the Windows Update troubleshooter, but no change).

I found this site that shows you how to update the definitions manually. It did update my defs to the latest version. I think I might have rebooted after I ran the program. Hopefully this fixed the problem but I have my doubts.

http://www.thewindowsclub.com/update...ally-windows-8

There is a thread here -> Windows 10 Update March 31 2017

which has been discussing this problem.

Thanks. I'll do any posting over there.

I also got that error. Now I update from windows defender and then try windows update. Now I don't get error as defender is updated.

Please check this thread On Windows Defender Definition Update error 0x80070643 - - Windows 10 Forums