"my computer has been blocked by trojan horse virus" - this message popped up on my mac today. what action do i need to take

No one can tell such stuff from outside your Mac.

Those sorts of things are usually a SCAM, and they can lock up your Web Browser. If they do, quit the browser or Force Quit if especially difficult.

Then hold down Shift when you re-launch the Browser to keep old pages from opening.

NEVER click on the items they invite you to.

NEVER call the phone number they give.

NEVER give a stranger access to your computer, when They contacted You.

NEVER send them money.

Did you supply the Admin password to install anything?

If not, there will be no permanent damage. So called "Virus Protection" programs are mostly useless. They tend to scan for things Macs do not get, alarm on things that are no threat to your Mac, and slow everything down. They give you a false sense of security. Nothing can replace your healthy skepticism.

If you are fearful of future attacks, you can turn off JavaScript in the Browser, but many sites (including Apple discussions) rely on JavaScript.

The same thing happened to me. I can force quit, but I can't get my browser to unlock. I've held down the shift key when restarting Safari, but it stays locked with the trojan horse virus message in front of the browser. Got any other suggestions?

If your Browser still puts up blocks with the Shift key held down as you re-launch, you may have adware:

Remove unwanted adware that displays pop-up ads and graphics on your Mac - Apple Support

HI grant I had this msg pop up call the number to speak to a technician which I did and regretting now. i had to type in some details for him telephone no for if our call dropped out and type in my email and password. He actually got into my MacBook and started scrolling through things and then said he found the problem and it would cost me $140 to have him fix it. I said I didn't have that money and after him persisting and even offering it for a cheaper price he gave up and closed the windows he was in and logged out. I've been able to get rid off the block but my worry is what he accessed and should I be worried and what can I do about it. Any help and info would be greatly appreciated thanks

jye morton

Change all your passwords now. If you had banking/financial information on your computer call your banking/financial institutions including credit card companies and inform them of the breach of security you had.

This crook installed some remote access software on your computer so you must uninstall that software.

You should change all the passwords as BobTheFisherman suggests.

If you either:

a) allowed unknown software to be installed, or

b) gave away your Admin password

... then your computer is compromised in ways that are hard to know. To secure your Mac again:

• If you do have a backup from before you granted access, you should ERASE your drive and do a full restore from before you granted access to those lying criminals.

• If you do not have a previous Backup, you should make one now, ERASE your drive, Install Mac OS from a fresh or saved download, and then re-install ONLY your files -- get your third-party Applications from their original sources, or restore them one at a time so that you Install exactly what you expect and nothing more.

If you need help in finding easy ways to make a Backup, just ask.

This sounds draconian, but is about the only way to assure that you do not still have "hitchhikers" that those creeps installed.

You probably do not have a virus. It's just a scam. DO NOT call any numbers they give and do not click on any help links they give you. Immediately Force Quit your browser by pressing Command-Option-Esc and click on the browser that has the scam on it. Then your browser should close. After that just to be safe, restart your Mac and you should be good to go!🙂