Is there a payload of some kind in the mp4? I doubt it.
That's good, because the Krelin and NSA are already hot on my trail!!
Your popup is NOT from the mp4 file. It's the app that opened when you double-clicked the mp4.
I suspect that by double-clicking, you were allowing the system to pick what app opened that mp4.
MUCH BETTER, and less likely to cause un-intended launches of apps that might "help" you in unknown ways:
Right-click your mp4, then, from the Open With drop-down, choose the app that you actually want to use, not the app that the system suggests. The two might be the same app, but now (with the right-click) you have more control over what happens.
Based on what I'm seeing, I have to disagree.
(I was already doing what you suggested above - see my notes in Post #9.)
Here is why I say that...
The video I captured using SnagIt is called: "Flo - Portrait of a Street Photographer.mp4" (It's an Op-Doc on the NYT times site, and very inspirational!!)
When I open that video, it opens in QuickTime. And as I recall, the first time I opened it, I right-clicked, and chose "Open With" and then chose "QuickTime".
Now when I double click on that video, it opens up in QuickTime.
For the video I created with ClipGrab: "You Clap for Me Now the coronavirus poem on racism and immigration in Britain.mp4", when I double-click on it, I am getting the 1st "unidentified developer" popup and then the 2nd "enter Admin credentials".
So, if I told macOS Sierra that I want it to open all .mp4's in QuickTime, the why is the second video I created with ClipGrab behaving differently?
Follow me?
Good or bad, it sure seems like there is some "signature" in that second file that macOS is questioning or needs verification on...
Now, MAYBE, there is some metadata/signature PER FILE, and by entering my Admin credentials, nothing bad will happen, and macOS Sierra will know anytime it sees a .mp4 created in ClipGrab that it should open it up in QuickTime?
OR, there could be some evil malware in that .mp4 that will lead to global annihilation and the end of the world as we know it?! 😮
The "known-good tool" is Malwarebytes.
By comparison, I don't
need (know) what ClipGrab does (still suspicious to me, but might be OK. What made you trust it? You seem more suspicious than I am
I trusted ClipGrab because people here said it was safe, and I researched it a little, and the reviews seemed okay on it, and it is open-source, but it is nowhere nearly as establish as say Firefox or LibreOffice.
Yes, Malwarebytes is well-known and respected by Mac users. It nicely covers its intended use, which is to find and remove known (by Malwarebytes) examples of malware, which on a Mac is usually adware of some kind.
The free version works well, you can find responses in these threads from Malwarebytes support folks, and the software does not take up precious system resources when it is not in use. It simply takes up a bit of space on your drive, and only asserts itself when you decide to scan the drive. The "bad players" get quarantined. You can delete those files on the spot. Quit Malwarebytes, until the next time.
And (I have a customer that does this) you can uninstall Malwarebytes from within the app. Then reinstall it the next time you want to scan. My friend runs it regularly every 3 months. Gets several "hits" on bad players each time. But, he accepts that because of the kind of sites that he goes to (all kinds of crafting and gaming sites - halls of evil for malware). I keep telling him that he needs to get the paid-for version, so that junk doesn't accumulate on his system. But, he says it's part of the territory. He just scans when the popups and re-directs get annoying - he has a high threshhold for that. I can't lose control of my web browser. He cares little.
Anyway, Malwarebytes works good. I trust it.
Hmmm...
I tried to read up on it yesterday, and the reviews I saw on a couple of sites made it sound like Malwarebytes does more harm than good, including filling your Mac up with more just?!
117 Reviews of Malwarebytes
This reviewer had some damning things to say: ShotBlocker on 10 August 2019
Personally, I find reviews on the modern web not very helpful, since they are either 5-stars or 1-stars, so who do you believe?
Obviously I respect your advice, but as you can see I'm not sure here.
Again, curious to see what you have to say about what I said above...
Thanks for the help so far!