jwcrim

Pretty strange. About a week ago I disabled the "automatic" feature of the updates then tried a few times again to manually download and install the definition update - and had no luck (installation failed). A week or so later I tried the manual update attempt from Defender again - but this time it installed as it should have. So now things appear to be functional.

The posts in this list by "sjk" might make some sense to you: http://groups.google.com/group/microsoft.public.windowsupdate/tree/browse_frm/thread/8990e0cb0b68985c/ecc4789bb1e4d938?rnum=1&q=0x80070643+defender&_done=%2Fgroup%2Fmicrosoft.public.windowsupdate%2Fbrowse_frm%2Fthread%2F8990e0cb0b68985c%2Fecc4789bb1e4d938%3Flnk%3Dgst%26q%3D0x80070643%2Bdefender%26rnum%3D1%26#doc_1b5ee63bd04d3473

I "Updated" installation (not definitions) from Control Panel and got (MpCmdRun.exe -RemoveDefinitions -All) to work: C:\Program Files\Windows Defender>MpCmdRun.exe -RemoveDefinitions -All Service Version: 1.1.1593.0 Engine Version: 1.1.1603.0 AntiSpyware Base Signature Version: 1.0.0.0 AntiSpyware Delta Signature Version: 1.0.0.0 Starting engine and signature rollback to default...Done! Service Version: 1.1.1593.0 Engine Version: 1.1.1603.0 AntiSpyware Base Signature Version: 1.0.0.0 AntiSpyware Delta Signature Version: 1.0.0.0 Ran "Update Definitions" from program but got same error message: The program can't install definition updates Error found: Code 0x80070643 What could be causing this?

Got the CLU to pause and was partially copied below. The problem seems to be that you can run it from the command line like this: C:\Program Files\Windows Defender\MpCmdRun.exe But not like this: C:\Program Files\Windows Defender\MpCmdRun.exe -RemoveDefinitions / -All In fact the program doesn't want to run with any modifiers including: C:\Program Files\Windows Defender\MpCmdRun.exe -? / -h Code: Usage:mpcmdrun.exe [command] [-options] Command Description -? / -h Displays all available options for this tool -Trace [-Grouping] [-Level] Starts diagnostic tracing -RemoveDefinitions [-All] Restores the installed signature definitions to a previous backup copy or to the original default set of signatures -RestoreDefaults Resets the Windows Defender registry settings to known good defaults -SignatureUpdate Checks for new definition updates -Scan [-ScanType] Scans for malicious software -GetSWE Exports information about software installed on your computer -GetFiles Collects support information

I should have mentioned that running the command line routine did not remove the definitions. Defender still can run them.

This is the Definition Version that shows on the bottom of the screen in Defender: Definition version: 1.0.0.0 created on 1/25/2006 at 2:29 PM. Look at the Defender directory I found a bunch of dll's and these: MpCmdRun.exe MSASCui.exe MsMpEng.exe I ran MpCmdRun.exe and it ran at the command line then dissappeared quickly. Running update again resulted in the same problem - can't install. I ran MsMpEng.exe with similar results. Seems pretty subborn.

Windows 2000 - all updates Had old copy of Beta version and uninstalled it. Installed new Defender as you suggested. Works fine with the initial definitions - thanks. I'm now running into trouble with the definition updates though. They load in but don't install. I get one of two errors: Installation Failure Error Code: 0x800B0109 or: The program can't install definition updates Error found: Code 0x80070643 appreciate any ideas