Trojan Horse warning on iMac after streaming site visit

It's unlikely that you actually have a trojan. It's most likely that you have allowed notifications from that website to be delivered. You can stop those notifications by following the guidance here: Customise website notifications in Safari on Mac - Apple Support

Transferring your data from the old Mac to the new may not transfer those notification settings, but if you find unwanted notifications happening on your new mac, you can follow the same guidance above to stop that.

Yes. First would be to stop using Chrome for anything. Remove it from your Mac.

Where is this popup occurring? If you also had Safari open while visiting that site, then it probably added itself to Safari's notifications. See if the following fits:

If these are sliding in the from the top right of the screen, a site you visited has given itself permission to send push notifications. Everything you're seeing is nothing but a scam.

Open Safari's preferences (Settings). Click on the Websites tab and then scroll down to Notifications. Clear any entries in the right hand window. You might find something similar in the Pop-up Windows heading below that. Block any you don't recognize.

Then if you want, uncheck the box to the right, as shown below here.

I personally can't think of any reason why I would ever want any website to push notices to me.

twcole1965 wrote:

I use mostly Google Chrome and turned off all notifications as soon as this popped up. I also ran an antivirus program that found nothing.

I agree wholeheartedly with Kurt regarding Chrome. Here are some testaments to Chrome:

Chrome is Bad

Video demonstrating above

Google Chrome Listening In To Your Room Shows The Importance Of Privacy Defense In Depth.

Unseen Burdens in Chrome That Can Lead a Mac to Lag

How to Manage the Secret Software That Google Chrome Installs on Your Mac\

Google Chrome's Sham 'Do Not Track' Feature

Also there is no reason to ever install or run any 3rd party "cleaning", "optimizing", "speed-up", anti-virus, VPN or security apps on your Mac.  This documents describe what you need to know and do in order to protect your Mac: Effective defenses against malware and other threats - Apple Community and Recognize and avoid phishing messages, phony support calls, and other scams - Apple Support.  

There are no known viruses, i.e. self propagating, for Macs.  There are, however, adware and malware which require the user to install although unwittingly most of the time thru sneaky links, etc.   

Anti Virus developers try to group all types as viruses into their ad campaigns of fear.  They do a poor job of the detecting and isolating the adware and malware.  Since there are no viruses these apps use up a lot of system resources searching for what is non-existent and adversely affect system and app performance.

There is one app, Malwarebytes, which was developed by a long time contributor to these forums and a highly respected member of the computer security community, that is designed solely to seek out adware and known malware and remove it.  The free version is more than adequate for most users.  

Unless you're using a true VPN tunnel, such as between you and your employer's, school's or bank's servers, they provide false security from a privacy standpoint.  Read these two articles: Public VPN's are anything but private and Security Risks: The Dangers of Using Free VPNs (eccu.edu)

Just some food for thought.

All such messages are scams presented by criminals, and should not be acted upon. The issue lies with the site you are accessing, not with your old Mac.

twcole1965 wrote:

Anyone else have a suggestion?

Besides everyone else's? Yes. Get rid of the antivirus program that found nothing. There is nothing for it to find. Rule 1 of Macs is don't install junk.