Security center is updating definitions for windows defender
They are complaining the Windows Defender update fails to install due to the 0x80070643 error code.Actually, this error has been randomly plaguing Windows Defender users for more than a year now, but Microsoft hasn’t been able to offer a solid explanation as to why this error appears, let alone a fix.To help provide continued and up-to-date protection, Microsoft researchers use these samples to analyze suspicious activities and produce updated antimalware definitions.We collect program executable files, such as files and files.We do not collect files that contain personal data, like Microsoft Word documents and PDF files.
Completely uninstall your old antivirus programs, restart your computer and Windows Defender should be able to install the latest updates.Multiple AV products can cause problems when installed and actively running on the same machine.See the question "Should I run Microsoft security software at the same time as other security products?The System File Checker tool repairs corruption in system files.Use this tool to verify whether Windows Defender is corrupted or not, which could explain why you can’t install the updates. If the issue still persists, we also recommend you to download this tool (100% safe and tested by us) to scan and fix various PC problems, such as file loss, malware and hardware failure. If you’ve found other workarounds, tell us more about your experience in the comment section below. Go to Microsoft’s Malware Protection Center portal 2.