Untrusted application launcher?
Some time ago, Ubuntu introduced a Security "feature", that would only allow trusted .desktop apps to be run, on other apps it would pop up a message.
Nothing new so far, However, said Message used to have a button to make the app "trusted", but that button doesn't exist anymore:
What's the point of this dialog?
Solution 1:
This dialog exists for your own safety, annoying as it is. To remove it, right click the launcher, click properties, and then go to the permissions tab and choose execute for the users you want to allow.
This will allow you to use the launcher from now on.
To do this for a large amount of launchers in the same directory, open a terminal (in the same directory) and run:
chmod +x *.desktop
Solution 2:
Right click the launcher and press "Properties", in the "Permissions" tab you will find a checkbox marked Execute, make sure that it is checked and Ubuntu will stop bugging you.