Windows 10: Do I need another anti-virus if have Defender on Windows 10?

I am running Windows 10, so have Defender. Do I need another anti-virus, e.g. Norton or Kaspersky?

:)

 

Anti Virus Problems

You should not be using more than one anti-vrus program on your computer. Read the
IMPORTANT NOTE about not using more than one anti-virus program in this

topic.

The inability to turn on Windows Defender 8/10 is typically the result of having a third-party anti-virus installed or failure to remove it properly (completely). Since Windows 8/10 Defender includes anti-virus protection, it is
disabled during the installation of another anti-virus program. If a trial anti-virus (i.e. McAfee, Norton, etc) came
preinstalled on your computer or you installed one, Windows Defender will be turned off (disabled). Windows Defender recognizes the install and automatically disables itself when other anti-virus products are used
to avoid conflicts. Windows Defender will remain disabled until that anti-virus software has been completely uninstalled. In some cases, you may need to download and run the anti-virus vendor's clean up tool to remove any remaining
remnants.

• Replacing your Anti-virus - List of Antivirus Uninstallers and Removal Tools
• Microsoft Wiki: List of anti-malware product removal tools by Stephen Boots,
  MVP

After removal of the third party anti-virus, Windows 8/10 Defender needs to be
activated if you choose to use it. When uninstalling the third-party anti-virus Defender should automatically turn itself on but sometimes you may receive a message indicating
your system has no protection...click here to turn on Windows Defender. If not, and Defender remains disabled, you will need to manually turn it on.

• How to turn Windows Defender On or Off in Windows 10
• How to turn Windows Defender On or Off in Windows 8

 

Is Windows Defender the only anti virus program I need?

Clarification, please.

Note that this is a Win10-specific thread.

Are you suggesting that Defender in Win10 (and Win8) does not include an anti-virus component or are you suggesting that Defender in Win10 (and Win8) does not provide sufficient (adequate; comprehensive) protection?

 

windows defender anti-virus

windows 10 v1709; i have removed all vestiges of third-party anti-virus software, but windows defender anti-virus will not run continuously. it keeps stopping and stating that another anti-virus is present. i have used the mfr uninstall utilities, revo-uninstaller,
and run a clean boot. nothing is working. anyone can help?? thx

Moved from: Virus and Malware / Windows Defender / Getting Started and Upgrading / Windows 10