To install Firefox on Mac, follow these steps: #Download the latest Desktop version of Firefox from http://www.mozilla.org and save the setup file to your computer. #After the download finishes, close all Firefox windows (click Exit from the Firefox or File menu). #Delete Firefox from the Applications folder. #Now, go ahead and reinstall Firefox: ##Double-click the downloaded installation file and go through the steps of the installation wizard. ##Once the wizard is finished, choose to directly open Firefox after clicking the Finish button. If the download gets interrupted, check the reasons for it: if it is a weak, slow connection, it would make sense to look for a faster point to connect. Please report back to see if this helped you!