When I try to open Keychain Access using Spotlight or Finder, I see an error saying: The Application "Keychain Access" is not open anymore. When I try to launch using open -a, I get:
$ open -a Keychain\ Access.app/ Unable to find application named 'Keychain Access.app/'
It was working fine until yesterday. A restart did not seem to help.
It looks like I shouldn't rely on Terminal's autocomplete while using open. Removing the trailing slash did not fix it. The new error is:
$ open -a Keychain\ Access.app LSOpenURLsWithRole() failed for the application /Applications/Utilities/Keychain Access.app with error -600.
Somehow it got fixed on its own. Among the things I tried was a restart, opening the app via the Terminal, and removing the plist from ~/Library/Preferences. None of those seemed to have had an immediate effect, if any at all, but Keychain Access is finally opening for me.