What is the difference between an "attempted terrorist attack" and your basic run of the mill "terrorist attack"?

If you’re on the wrong end of the gun probably nothing. And religion doesn’t change anything.

I would not even raise it to the level of a terrorist attack, it was just an average criminal act, nothing more.

There must be victims, innocent victims, casualties.
Otherwise the media spin wagon will deem it as an attempt.

I agree with @ucme. In this case the intended targets were almost certainly the artists and patrons of the event (not the security personnel guarding the perimeter). The terrorists weren’t able to kill any of their intended targets

So, since a whole lot of innocent people were not slaughtered, it is really not a terrorist attack. Is that what I am hearing? And they were in fact innocent. They may have been saying something that the jihadis did not like, but tough shit. They are entitled to say it. So a terrorist attack is only a terrorist attack until or unless lots of people are murdered. Otherwise, it is a random expression of frustration with mitigating circumstances. Is that correct?

@josie No, it’s an “attempted terrorist attack” not “a random expression of frustration with mitigating circumstances.”

I guess people might draw the line between any activity on the terrorist’s part and whether their main aim were carried out.

I think the word “attack” is not limited to successful efforts, so I agree that it’s still a terrorist attack, even if no one were killed or injured at all.

@josie You’re hearing it from mass media, i’m just passing that fairly open information on.
Interesting that appears surprising to you, don’t shoot the messenger man.