error code #0x8050800c

Question

Microsoft defender #0x8050800c error code...what does this mean?

Answer 1

Error code: 0x8050800C
Message	ERR_MP_BAD_INPUT_DATA
Possible reason	This error indicates that there might be a problem with your security product.
Resolution	<ol><br><li><span style="color:black">Update the definitions. Either:</span><br><ol><br><li><span style="color:black">Click the<br></span><strong><span style="color:black">Update definitions</span></strong><span style="color:black"> button on the<br></span><strong><span style="color:black">Update</span></strong><span style="color:black"> tab in Windows Defender.<br>Or, </span></li><li><span style="color:black">Download the latest definitions from the<br></span><a href="https://aka.ms/wdsi" target="_blank" rel="noreferrer"><span style="color:#0050c5">Windows Defender Security Intelligence site</span></a><span style="color:black">.<br> Note: The size of the definitions file downloaded from the site can exceed 60 MB and should not be used as a long-term solution for updating definitions.<br></span></li></ol><br></li></ol><br>    <br>Run a full scan.<br> <br><br>    <br>Restart the device and try again.

https://docs.microsoft.com/en-us/windows/security/threat-protection/windows-defender-antivirus/troubleshoot-windows-defender-antivirus

This is often a temporary error, and I suspect that it does in fact indicate a programmatic error in Windows Defender – but I’ve only seen this error once, and that was after a test cleaning with Ccleaner. So I think the error in my case was caused by Ccleaners unfriendly removal of Defender’s tracking data, and that the issue might more generally be caused by other system cleaning and optimization utilities.

GreginMich

Answer 2

0x8050800c

There might be a problem with your security product.

You should check for available updates and try again, or

reinstalling your security product

~

Answer 3

See this archived reply from an earlier thrəad:

<<https://answers.microsoft.com/en-us/protect/forum/protect_defender-protect_updating/windows-defender-security-definition-update/0cc4fd2c-430c-4bc6-be4a-e97120673db5>>