Some users—including one of my two Catalina test Macs—have experienced issues using Witch in Catalina, as evidenced by a locked-up System Preferences panel or unclickable Witch interface elements.

You can read through this post for more details on the problems and what we think is going on, but if you’re having similar troubles with Witch, you most likely just want to make it work right…

The solution

The exact solution depends on whether you installed Witch for all users or just the current user (current user is the default presented by macOS during installation).

If you’re not sure how Witch was installed, navigate in Finder to your user’s Library > PreferencePanes folder. If you see Witch.prefpane, it was installed just for the current user. If there’s no Witch.prefpane there, but Witch is installed, then it was installed for all users.

Once you know how Witch was installed, quit the System Preferences application, and launch Terminal, in Applications > Utilities.

If Witch is installed for the current user, paste the following command, press Return, and then enter your admin user’s password when prompted (you must be logged in as an admin user to run these commands):

sudo xattr -d -r com.apple.quarantine ~/Library/PreferencePanes/Witch.prefPane/

If Witch is installed for all users, use this version of the command, followed by the same Return/password process as above:

sudo xattr -d -r com.apple.quarantine /Library/PreferencePanes/Witch.prefPane/

Now reopen System Preferences, switch to the Witch pane, and hopefully you’ll find yourself with a fully functional Witch app—with a couple of minor exceptions. If this solution does not work for you, please open a trouble ticket and we’ll try to figure out what’s going on.

The first exception to the “fully functional” statement is that Dark Mode support is broken. This is not our fault, and there’s nothing we can do about it until Apple fixes the bug—sorry, Dark Mode users!

The other exception is that the panel will jump around oddly as you switch between Witch’s tabs; this is something we didn’t see in testing until the final beta release. It seems Apple changed the rules, and we’re no longer allowed to resize the System Preferences panes. We’ll have an update out very shortly to address this issue. For now, if you get to a screen where you can’t see the tab bar in Witch’s panels, just jump out (by clicking the Show All icon, for example), then go back in.

Now, if you’d like the nitty-gritty on what we think is going on, keep reading…

The symptoms

After loading Witch, you may find that Witch is working, but you can’t use its System Preferences pane at all—any attempt to load the pref pane will cause a multiple-minute freeze in System Preferences, and once it does load (it will if you give it time), you can’t click on any of the items in Witch’s panels. Disabling and enabling Witch will also be met by very long delays.

Another set of symptoms is that you get an error message saying “Could not load Witch preference pane.” Or another saying “Witch-Fatal Error.” Or another saying “Witch.prefpane can’t be opened because Apple cannot check it for malicious software.” Although all different, these are all related to the same problem.

The problem

Figuring out what was happening here was tricky, because it’s not happening to all users (we’ve had only a handful of reports), and until recently, neither Peter nor I could replicate the problem on our own Macs. But then I got “lucky,” in that one of my Catalina Macs exhibited the symptoms.

After looking into a lot of possible problem sources over the weekend, we’ve discovered that the problem is caused by a macOS feature called file quarantine, which flags apps—including System Preferences panes—downloaded via the internet (at least in Safari). When you try to open one of those files, you’re warned via a dialog box that the file that was downloaded from the Internet, and asked if you’re sure you want to open it. If you click the Open button, what should happen is that the OS then removes the “quarantine flag” from that file.

Sometimes—for whatever reason—the quarantine flag doesn’t get removed, which leads to that dialog appearing over and over again. (This seems to happen more often with System Preferences panes than with applications—so much so, in fact, that we have an entry in our FAQ about this very problem.) At least, that’s how things worked in Mojave and older macOS releases.

In Catalina, however, it seems that if the quarantine flag isn’t cleared, you don’t see the warning dialog. Instead, at least with Witch, it appears to install and load, but then produces the symptoms noted above, all without any feedback to the user about the state of the quarantine flag. The fix discussed above simply removes the quarantine flag from the Witch System Preferences panel, and that change magically lets Witch start working properly again.

As noted, we don’t know why the system is behaving this way, but in my own testing—and testing with a few users who reported the problem—clearing the quarantine flag has fixed the problem for everyone so far.

Tags: macOS Catalina

This entry was posted on Sunday, October 13th, 2019 at 2:24 pm by Rob Griffiths, and is filed under Products, Witch. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.