Back up and virus

If you have malware, TIme Machine will back it up. To check for malware you can run  Malwarebytes. Malwarebytes was developed by one of our own colleagues here in ASC and is about the most proven anti-malware software for Mac.

Even if it isn't malware but just some directory corruption, TM will back it. As Allan says, details will help.

For starters, your Mac will not get a virus.

How about providing the details which make you think you MacBook might be infected by a virus.

if it is a scam, maybe just maybe it will come also into macOS and se malwarebytes, if it is a virus it will not transport from windows to macos.

""And as it turns out, Malwarebytes for Windows will catch things that Windows Defender misses. Personal experience.""

correct.

Although Windows10 latest update Defender is extremely good. No need anymore for the (usual) virus scanner).

That may be but since I started using Windows defender I have never (knock on wood) had to use MalwareBytes for Windows as I had done in the past. Windows Defender works very well if kept current with updates.

Indeed Bob, my experience too, see above. The built-in Defender is updating itself continuously and working very very good (Win1oPro). Still, I use Malwarebytes (never permanently working) from time to time to be satisfied.

Are you running the Windows Defender in Windows? If you get a web pop up saying you have a virus it is a phishing scam.

There is a version of Malwarebytes for Windows that you can try.

https://www.malwarebytes.com/premium/

And as it turns out, Malwarebytes for Windows will catch things that Windows Defender misses. Personal experience.