how to avoid the "downloaded application" warning for a Standard User This is a followup on this post of mine: Application permissions for Standard user

I'm now running MacOS High Sierra 10.13.5 and this problem is still irritating.

I use my Mac as a Standard user. When I first set it up, all applications were downloaded/installed using the Admin user.

When using my Mac as the Standard user, every time I go to run an application I get the following message:

"Whatever.app" is an application downloaded from the Internet.
Are you sure you want to open it?


With the options for Cancel and Open. Of course I choose Open and everything works fine.

Now, I am used to this notice appearing the first time I try to run an app from the internet. My problem is that it appears every time.

Note that I am not asked for any Administrator credentials, and these apps have already been installed to the /Applications directory as an Administrator.

I have tried with a different Standard user and still have the same issue. I have also already used Disk Utility to repair the drive permissions, just in case.

How can I make this notice appear only on the first run?

==========================================================

More details:

If I install an application, while logged in as the Standard user, but authenticating as the Administrator, then it only warns me about the Application on the first run, and then never again, as long as I am still logged in as that Standard user.

But all the applications I installed while logged in as Administrator give me a pop up warning every time if I try to run them while logged in as a Standard user. 

There is a "solution" to this problem, but it is so incredibly inelegant. For every application I downloaded and installed, while logged in as Administrator, simply installing the application is not enough. I must actually login as the Administrator and launch the application at least once to clear the warning for all other users. This seems incredible silly. Surely there must be a better way to accomplish this?
The basic problem is that the applications are all marked as being in quarantine (they have the "com.apple.quarantine" extended attribute) because they were downloaded from the net. Running the app removes the quarantine attribute if the file permissions allow you to modify the file (e.g. if you're the file's owner -- in this case, the Admin user). If you don't have permission, the quarantine attribute stays, and you keep getting the "downloaded from the Internet" message over and over.

Solution: one way or another, you need to remove that quarantine attribute. You can do this for a bunch of apps at once in Terminal.


First use su (switch user) to switch to your admin user (type in "su", then a space, then the account name of your admin user, then press return and enter the admin account's password; note that the password won't be displayed as you type). It should look something like this:

Dans-Mac:~ dan$ su adminacct
Password:
bash-3.2$

If that works, type in "xattr -r -d com.apple.quarantine", then a space, then drag all the apps you want to dequarantine from the Finder to the Terminal window; when they're all listed, press return. Note that you can drag them one at a time or in groups, whatever's convenient. Something like this:

bash-3.2$ xattr -r -d com.apple.quarantine /Applications/BBEdit.app /Applications/Firefox.app