I have two hard drives on my machine (Lion). One contains the regular copy of OS that I use everyday, the one has a slightly older copy of the OS that I keep as a backup (in case the first drive stops working).

A somewhat annoying problem is that whenever I right-click on a file and go to "Open With", two entries for each application I have will show up in the cascading menu, one from each copy of an application from the two drives. The one from the everyday-use-drive will have a newer version because I update them regularly (This way I can tell which app to use).

I looked around the documentation and it seems like I can use Launch Services


but I haven't found any example that does exactly what I am looking for. Any ideas? Thanks!

  • Unmount the other partition?
    – Daniel Beck
    Oct 21, 2011 at 12:28
  • I don't want to do that because I have some other files (that I actively use) in the same drive. Oct 21, 2011 at 17:34
  • You can also mount the drive as noexec, which should disable apps on that drive to show up in "open with" menu because they are no longer executable.
    – Joy Jin
    Mar 27, 2021 at 8:33

1 Answer 1


Try this procedure:

  1. Exclude your second drive from Spotlight indexing (or, if you want to keep access to it via Spotlight, just exclude its /Applications folder) by dragging its icon into the Privacy pane of the Spotlight System Settings. This will preclude Launch Services from seeing the apps on the drive and re-registering them in the next step.
  2. Make Launch Services reload the list of available apps with the command /System/Library/Frameworks/CoreServices.framework/Versions/A/Frameworks/LaunchServices.framework/Versions/A/Support/lsregister -kill -r -all local,system,user. As apps on the second drive are not available via Spotlight anymore, the new database will only contain those on your main drive.
  3. Restart Finder to rebuild its Open With context menu (Option-right click on its Dock icon to get the restart option, or do killall Finder in Terminal).
  • awesome! Worked perfectly. Oct 21, 2011 at 17:33
  • but then "find" (files and folders) feature won't work on that external drive :(
    – Nimbuz
    Aug 1, 2012 at 7:20
  • @Nimbuz: that is so if you exclude the whole drive, as the find feature is Spotlight. However, as I pointed out in the answer, you can keep finding anything but apps by only excluding /Applications on the external drive.
    – kopischke
    Aug 2, 2012 at 8:03
  • There is no option to disable indexing for external drive only. You just enable or disable it.
    – Nimbuz
    Aug 3, 2012 at 7:55
  • 2
    @Nimbuz: You can add individual folders to Spotlight’s privacy pane from any drive – external or internal. Just follow the instructions in the answer.
    – kopischke
    Aug 3, 2012 at 9:11

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