Question: All Zip / DMG files state 'is damaged and can't be opened'
I have just bought a new MacBook Pro and upgraded to macOS High Sierra. I have used Migration Assistant to transfer my files over from my old MacBook pro (running Sierra).
On my new MacBook every time I download a zip/dmg file when i try to open it it states //Filename// 'is damaged and can't be opened. you should move it to the trash.'
I have tried downloading several different files (Firefox, Spotify etc) and they all state the same thing. I have tried downloading and using Stuffit and The Unarchiver and the same thing happens.
Any help anyone could offer would be greatly appreciated.
MacBook Pro TouchBar and Touch ID, macOS High Sierra (10.13.1)