[Avid]

Also, this might help to make sure you have the complete download...

In the Mac Finder, go to the menu bar at the top, choose Finder > Preferences
Click on "Advanced", and check the first box: "Show all filename extensions"

If the download is complete, the full file name should be this:
Pro_Tools_902_Updater_70918.dmg

If you do a "Get Info" on the file, it should show this size, or very siimilar:
1.87 GB on disk (1,873,368,111 bytes)

If your download shows a smaller size, or shows the extension as ".dmg.dlm", then it is a partial download. The .dlm extension indicates that it is an incomplete download manager file. The .dlm extension goes away when the download is complete.

I tested the download on the latest non-beta versions of Firefox, Safari, and Google Chrome, and all downloaded and opened uncorrupted in my tests. So I'm fairly certain that the files are not corrupted at the hosting end.