I often get the dialog box warning me that I'm opening an application for the first time. But, it isn't the first time. Some of these are applications that I use daily. enter image description here

I seem to be getting more of these after an OS upgrade, almost as if some database got reset. Can I do something to get these warnings to be generated properly?

  • One more idea for someone with a similar problem: Each time the application (RStudio, recently updated) was called as a subordinate command (as part of opening an RProject file, long-standing shortcut), I got the warning dialog. After I opened the application directly once, using the shortcut no longer triggered the dialog.
    – InColorado
    Nov 17, 2022 at 19:55

3 Answers 3


This warning pops up every time an application wants to register a URI handler (a something:// protocol). Normally, your approval is saved by LaunchServices, but that database can become corrupted. Try resetting it by doing a

/System/Library/Frameworks/CoreServices.framework/Versions/A/Frameworks/LaunchServices.framework/Versions/A/Support/lsregister -kill -r -all local,system,user

in Terminal. The warnings should pop up once for each application again after that, then be gone for good. If they keep coming, something is resetting the database on its own (a clue would be that the default browser / mail app / RSS app / FTP app you set keep resetting to the Apple provided ones).

  • Awesome answer. Have you found items like system preference panes getting this message more often in 10.7.2?
    – bmike
    Nov 4, 2011 at 18:13
  • @bmike: not at all – which is why I think OP’s LaunchServices DB is (was) either corrupted, or something resets it.
    – kopischke
    Nov 4, 2011 at 19:14
  • Thank you. I'm seeing some specific apps like ScreenSync never get the quarantine bit cleared in 10.7.2. Even if I rebuild the launch services database with your command, it still prompts me each time I log in (and it starts itself). I have had to resort to using xattr to manually delete the quarantine bits....
    – bmike
    Nov 4, 2011 at 19:22
  • @bmike: the quarantine bit triggers another warning dialog, the “This application has been downloaded from the internet (yadda, yadda)” one.That has nothing to do with LaunchServices.
    – kopischke
    Nov 4, 2011 at 19:33
  • Now I'm confused. I get the same dialog on the pref pane that needs a quarantine bit to be cleared by hand. cl.ly/BZKm Is the difference the wording at the bottom of the dialog - one mentioning a web page and the other a location of the app?
    – bmike
    Nov 4, 2011 at 20:51

I had the same problem (only with SourceTree, after an update), and seeing @kopischke's answer reminded me of another Ask Different thread, on another LaunchServices database problem:

Why does my Mac's list of "Open with" applications start listing the apps twice and sometimes three times?

The LaunchServices reset command provided there is slightly different from the one @kopischke provided:

/System/Library/Frameworks/CoreServices.framework/Versions/A/Frameworks/LaunchServices.framework/Versions/A/Support/lsregister -kill -r -domain local -domain system -domain user

I tried that, and it solved my "Opening application for the first time" problem. But it did not require me to re-okay every other application as well (only a few; I didn't see an obvious pattern in which). So it may be worth trying this before trying the earlier suggestion.


Neither of the answers using lsregister worked for me. What did work was to manually remove the App from quarantine:

xattr -d com.apple.quarantine /Applications/MyApp.app

(replace MyApp with the actual name)

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