I accidentally associated a file type with an application that doesn't work with that particular file type. (There is no application installed on my system that works with the file.) I would like to remove the default application association. I found this Q&A How to remove the default application for opening a file? but it seems like it's not exactly what I want and outdated for Catalina. For instance, there is no ~/Library/Preferences/com.apple.LaunchServices.plist on my system. I would like to execute a command that removes the association for the one single file extension, not remove all of the associations for an application as this one appears to suggest. I have been able to dump the database using lsregister but I'm not sure what command could be used to remove one entry.

  • RCDefaultApp still works on Catalina, according to reports. [Can't test myself, I'm still on Mojave]
    – Tetsujin
    Mar 7, 2020 at 13:41
  • 1) It does not work on Catalina. Or at least my installation of Catalina. Even after unblocking it, System Preferences displays an error when I attempt to use it 2) I would like to understand what commands/file modifications can accomplish this Mar 7, 2020 at 16:02

1 Answer 1


A Catalina-compatible alternative to RCDefaults can be found here:


It provides a preference pane and a command line utility for setting the default app of any file type.

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  • This doesn't appear to do what I'm looking for. I installed it via brew but the pref pane doesn't seem to have the ability to associate or disassociate an extension and an app. I scoured the URI Schemes, Uniform Type Identifiers and Applications and none of them have the extension. I know it says it has a CLI but I have no idea where to start and there are no docs. Mar 8, 2020 at 13:22
  • @RobbVandaveer Find the UTI of your file type, then select the application options. See the screenshot.
    – benwiggy
    Mar 8, 2020 at 13:57
  • As I said in my comment, I scoured the URI Schemes, UTIs and Applications and none of them have the extension in question. The extension still has the undesired associated in Finder however. Mar 9, 2020 at 14:09
  • @RobbVandaveer What is the file type?
    – benwiggy
    Mar 9, 2020 at 14:25
  • Nuget Package, extension nupkg. If I dump everything using lsregister, I can see an entry for it: handlerpref id: 3144 (0xc48) URL scheme: nupkg all roles: com.aone.keka Mar 9, 2020 at 18:43

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