Hey-- so I just remove Avast antivirus free program, and I installed new program, called Avira, but I see icon the bottom right. so it is called Window Defender,so which should I keep it or to remove? which one. just wondering.
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With another AV installed Defender will not be providing real time protection, but by default it will still periodically scan the files on the PC. This scan shouldn't interfere with your other AV and provides a useful second level of protection, I'd keep it.
It should do no harm keeping it and may help protect you, but it is an optional feature. There's more on Defender's 'Limited Periodic Scan' in this tutorial, including how to turn it off if you wish.
Turn On or Off Limited Periodic Scanning in Windows 10
It should scan quietly in the background and not slow you down noticeably. I'd say keep it.
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