Q: http://macsecurityalarm.com

Do not call that number. It's a scam.

The interference with Safari is caused by malware.

If you can't do this using Safari, hopefully you have a backup browser installed such as Firefox or Chrome to download and run this free utility > Malwarebytes | Free Anti-Malware Detection & Removal Software

Or you can remove the malware/adware yourself by following the instructions here >  Stop pop-up ads and adware in Safari

After you have removed the malware make sure to remove Safari cookies by going to Safari > Preferences > Privacy then click: Remove All Website Data then quit and relaunch Safari.

message edited by:  CS

Don't use any kind of "anti-virus" or "anti-malware" product on a Mac. There is never a need for it, and relying on it for protection makes you more vulnerable to attack, not less.

Your problem is most likely not caused by malware. It's a Web scam that only affects the browser, and only temporarily. There are several ways to recover.

1. The easiest thing to do is to force quit the browser. Relaunch it by holding down the shift key and clicking its icon in the Dock, the LaunchPad, or the Applications folder.

You will lose the state of other open tabs and windows. Either Step 2, Step 3, or Step 4 may enable you to keep that state information. If those steps don't work, fall back to Step 1.

2. If there is a checkbox in the popup marked

          Don't show more alerts from this web page

check it, then close the popup.

3. Press the key combination command-W to close the tab or window. A huge box will pop up. Press the return key and both the box and the page may close. If that doesn't happen, press and hold command-W. You may hear repeating alert sounds. While holding the keys, click the OK button in the popup. A different popup may appear, which you can cancel out of as usual.

4. From the Safari menu bar, select

          Safari ▹ Preferences... ▹ Security

and uncheck the box marked Enable JavaScript.

After closing the malicious page, select from the menu bar

          Safari ▹ Preferences... ▹ Privacy ▹ Remove All Website Data

to get rid of any cookies or other data left by the server. Open the Downloads folder and delete anything you don't recognize.

Since my computer was "locked" I went onto my iPad and I Followed the 1st instruction by force closing Safari. I then reopened it holding down the shift key. Problem solved.

THank you.