Screen with warning of Virus and malicious applications pop up screen

Started when I got notice to update Flash player.

That wasn't Flash. You installed a newer forum of malicious adware that intentionally blocks access to certain sites. All in the attempt to prevent you from removing it and believing you need to call whatever crook's phone number is displayed.

In the future, never, ever believe any site that tells you to update Flash, Java, that you need a codec, or anything else that comes from them. The one and only place to acquire Flash is from Adobe. Java from Oracle (for the latest version), or Java 6 from Apple.

Restart the Mac in Safe Mode (restart and hold down the Shift key). This will prevent all but the most basic OS functions from loading. From there, you'll be able to download and run MalwareBytes for Mac. It will look for, and offer to remove any garbage it finds.

The screen may flicker or draw with strange looking horizontal strips as Safe Mode boots. That's normal since the OS is using a very generic video driver instead of the one meant for your graphics hardware.

If that was a popup from a website that downloaded a file directly from them, that wasn't Flash you installed. At minimum, it was adware. Hopefully, nothing worse.

It's possible it may be easily removed by opening Safari's preferences and disabling any extensions you don't recognize. If that stops the ads, remove the disabled extension.

If the ads persist, download and run MalwareBytes for Mac. It will look for, and offer to remove any garbage it finds.

In the future, never, ever believe any site that tells you to update Flash, Java, that you need a codec, or anything else that comes from them. The one and only place to acquire Flash is from Adobe. Java from Oracle (for the latest version), or Java 6 from Apple.

You visited, or were redirected to a site that pushed the same download over and over to your Mac. These are generally associated with a scam page saying your Mac is infected.

You did the correct thing by shutting down Safari and simply deleting everything in the Downloads folder. You don't need to do anything else - other than not visiting that particular link again.

It's a Scam, see > Avoid phishing emails, fake 'virus' alerts, phony support calls, and other scams - Apple Support

Fake. Scam. There is no way for any remote device can detect what is on your computer through a web browser. Despite anything it says, it's not from Apple, and neither is that phone number.

You should be able to simply click the Back button. A popup should appear asking if you want to leave the page.

Sites CAN determine your Router's IP Address, and can use it to look up your rough location.

Sites CAN determine what Browser you SAY you are using (but this can be spoofed with settings in many Browsers).

NO ONE can determine whether your Mac has a Virus or other malware from outside your Mac. (It is somewhat difficult to determine from INSIDE, even when you go looking for them.) These are ALWAYS a SCAM.

Why would you ever trust an outsider who provides such unsolicited advice -- they will lie to you to get your money or access to your computer.

No legitimate company works this way -- they just shut off your account and just wait for you to contact them.

Restart the Mac in Safe Mode (restart and hold down the Shift key). This will prevent all but the most basic OS functions from loading. From there, you'll be able to download and run MalwareBytes.

The screen may flicker or draw with strange looking horizontal strips as Safe Mode boots. That's normal since the OS is using a very generic video driver instead of the one meant for your graphics hardware.

I had been through the same problem since six months, for my luck I've found an app called Malwarebytes (malwarebytes.com) and scanning with that detected lots of unwanted malwares in my applications, including MacKeeper. You will be asked to restart after deleting all those... Happy computing....

Yes, it's okay. This assumes you didn't open or run any of the files the site dumped into your Downloads folder. All you need to do is delete them.

The screen you saw is the same as all of these scams. No one, in any way, can know what is on a remote computer through a web browser. Anything any such site says about you being infected with something is a lie. Period.

Remove Bitmedic. There is absolutely nothing useful with any AV software for the Mac. There are no viruses to stop, and any Trojan will go right past it.

I had this problem all week with my MacBook Air, specifically on my most frequently visited (very legitimate) site. Several seconds after I open the site, a popup window with scam ads appear, and whenever I interact, I get redirected to the window saying "your Mac has been infected with 3 viruses".

I tried everything described here, including wiping my hard drive clean and re-installing my OS.

Eventually I took my Mac the doctor and the moment I connected to their wifi network, the problem disappeared. It gave me the clue that the issue is with my wifi network, not my Mac. I googled "malware in router" and changed DNS servers according to the information I found.

Problem is now solved. I connect to "openDNS" without any further annoying popups or virus threats.

You can force quit Safari. Press Command+Option+Esc. Choose Safari in the list and click Force Quit. Close the window.

Now, hold the Shift key down and relaunch Safari. That tells it not to load any previous web sites from the previous session.

I've gotten the same thing. It happens in Chrome as well as Safari. Force Quit is the only way out of it. Two differences:

In Chrome I get multiple files trying (and failing) to download. Keep getting the download indications at the bottom of the window.

In Safari it keeps opening finder windows.

The website this comes from has an .ml domain, which signifies the country of Mali.

It’s very easy to clear. In most cases, all you need to do is Force Quit Safari, then hold down the Shift key while relaunching it. That tells Safari not to load any sites from the last session.

Appearing to be stuck is nothing but a browser trick. Whether it’s an actual page or a popup, JavaScript is holding you there. When you attempt to leave the site or close the popup, the last JavaScript command is to reload the same thing. You’re really just stuck in a simple loop.

As far as avoiding them, quit going to the sites that cause them to appear. They don’t show up randomly. You have to visit a particular site that displays this junk, or a site that redirects you to one. Keep visiting the same sites and you’ll keep getting the same result.

If you keep going to the same site, you'll keep seeing the same scam. You also may have installed adware that is redirecting you to the site.

Check the installed extensions in Safari's preferences (if there are any). Disable and remove any you don't recognize. Also, check under the General tab to see if your homepage has been changed.

Finding the name of a site in the Websites tab doesn't mean much, other than the site stuck its name in one of the headings after you visited the bogus site.

Regardless, it's the same as, literally, any site the makes any such claim. It's fake.