That could be the answer since, I recently got this device. So a lot of software had to be reinstalled. But that's not what I'm worrying about. I worry about windows defender not detecting it. And it's not that I got infected and the very moment I noticed it. I think I was infected for more then 10 days. There was no way of knowing, until I tried to make a transaction and made this discovery. That's what I don't like about it. This sly virus, not showing up anywhere until someone tried something related to crypto.
Have you checked on any of your recent programs that you've downloaded? There's a possibility that the reason why the Windows Defender didn't detect this is probably because it's a Trojan and an advance one at that as Windows Defender is already a good antivirus program so you can probably check on the previous downloads that you've done. Is this virus only a thing for computers? Or is it on mobile too? It's a scary thing for me because I'm not really checking too much on which address I would send my bitcoin so I'm a likely victim to this, good thing I don't do a lot of transactions.
if it applies to mobile phones it will be very easy when newly installed applications will of course require approval for some access on the smartphone.
applications downloaded from official sites may have very little risk. but on a PC or other device, we often download and install applications provided by other developers.
If a virus has been detected, reinstalling your device is the most appropriate choice to clean everything. As OP experienced, it's possible that the antivirus really didn't detect the virus until we realized when it was connected to a crypto wallet. and the situation is just waiting for us to be careless.