pkg file extracting instead of installing?

Question

Recently I noticed my pkg updates are being extracted rather than installed. (for example the MS Office update wanted to extract the file)

Is there a way to ensure that pkg files are installed?

Answer 1

Most obvious cause would be that some other app has taken over the .pkg extension - maybe a file compression utility.

Find any .pkg file & Cmd ⌘ i to Get Info.
Where it says Open with, select Installer, then Change All