Quicktime & M4A File Can't Open "Unidentified Developer"

[adamjackson]

• MacBook Pro 15" El-Capitan (Latest Public OS Release)
• iCloud Drive
• File Located on iCloud / Desktop / Reviews (folder)
• File called New Recording 6.m4a at 3.8 Megabytes
• iCloud Drive fully synchronized

I get this when I double click:

If I open Quicktime player in Applications by Right Click / Open, I get no window and then I can do Apple+O and choose the file and it opens fine.

Any reason this would happen? It's a file recorded by Voice Memos on iOS and saved to iCloud Drive.
[doublepost=1481902069][/doublepost]Info Window:

 

[Kissmyne]

To resolve this issue, control+ click on the file that you are getting this prompt with, and select open from the menu that becomes available, you will get a prompt similar to the one driving your initial post, however there will be an "Open" option, after you click that.. you will not be prompted again(typically) for that file. Please be aware that macOS updates may trigger this prompt in the future.

 

[Nermal]

I've run into this too. You'd think it would only block actual executable files, but I've had it block plain text files too...

 

[Kissmyne]

I've run into this too. You'd think it would only block actual executable files, but I've had it block plain text files too...

It makes sense that they do this, especially with the prevalence of malware infested attachments and file extensions being hidden when it comes to Windows machines(which macs are designed to run alongside)

 

[adamjackson]

To resolve this issue, control+ click on the file that you are getting this prompt with, and select open from the menu that becomes available, you will get a prompt similar to the one driving your initial post, however there will be an "Open" option, after you click that.. you will not be prompted again(typically) for that file. Please be aware that macOS updates may trigger this prompt in the future.

Yes. I did this and that's how I opened each of the files eventually.

My question is. This is an Apple feature (iCloud Drive). and the files opened just fine yesterday. Something happened overnight to cause this w/o any re-syncing.