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 but it seems like it's not exactly what I want and outdated for Catalina.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 '20 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 – Robb Vandaveer Mar 7 '20 at 16:02

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. – Robb Vandaveer Mar 8 '20 at 13:22
  • @RobbVandaveer Find the UTI of your file type, then select the application options. See the screenshot. – benwiggy Mar 8 '20 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. – Robb Vandaveer Mar 9 '20 at 14:09
  • @RobbVandaveer What is the file type? – benwiggy Mar 9 '20 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 – Robb Vandaveer Mar 9 '20 at 18:43

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