Opening app for first time problem

[zamboknee]

It seems that after restarting/turning on my Macbook Pro Retina I'll get a prompt telling me I've 'opened up an application for the first time'.
The problem is that I haven't opened it for the first time, I've opened them up quite a bit with this computer and operating system.
Apps I've noticed it on are Reaper, Musicbox and a couple others that I can't recall right now but they're 3rd party applications.

 

[Fishrrman]

I get the same warning now and then, on both Yosemite and Mountain Lion, usually after running some maintenance task.

I just click "open", and then move on...

(i.e., don't waste time worrying about it.)