Downloaded dmg files have wrong labels and don't work
I got a new iMac two days ago and I'm trying to download the third-party apps that were on my old, dead Mac. When I downloaded Firefox the disk image was labelled OpenOffice (an app I downloaded earlier); when I downloaded Evernote the dmg was named Spotify (another app I downloaded earlier). In each case when I double-click the dmg and try to move the left-hand file into the Applications alias...
I get the error message:
iMac with Retina 5K display, macOS High Sierra (10.13)