Possible Duplicate:
How do I install an application from a disk image?

I just got my first Macbook Pro yesterday and one of the first thing I did was to download and install Mozilla Firefox web browser onto my laptop. After I dragged the firefox icon to the application folder, everything was fine except I was left with a "Firefox 15.0.1.dmg" file that I didn't know what to do.

I experimented with it and tried ejecting the "disk" and dragging it to trash and emptying it. After I did that the Firefox icon on my dock went black and there was no response when I clicked the FireFox icon on my dock.

So I had to redownload and reinsintall everything to make it work again.

Are these dmg files stuck in my computer forever? My download folder is getting unnecessary big


1 Answer 1


A .dmg file is kind of like an USB stick in a file and can be handled more or less the same way. To install from a .dmg file you usually do the following:

  • double click the .dmg to make its content available (name will show up in the Finder sidebar), usually a window opens showing the content as well
  • drag the application from the .dmg window into /Applications to install (may need an administrator password)
  • wait for the copy process to finish
  • eject the .dmg (by clicking the eject button in the Sidebar)
  • delete the .dmg from Downloads
  • How do I install to a directory other than Applications? can I only install to to Applicaions? Jan 23, 2018 at 15:12
  • 1
    @SoftwareSavant Just drag the .app file to any directory you want.
    – nohillside
    Jan 23, 2018 at 18:51
  • Thanks, I just realized this. Getting used to Mac's. It is going to be a wild ride. Jan 25, 2018 at 23:21

Not the answer you're looking for? Browse other questions tagged .