diff --git a/modules/juce_core/native/juce_mac_Files.mm b/modules/juce_core/native/juce_mac_Files.mm
index befd4944f5..b056622f3d 100644
--- a/modules/juce_core/native/juce_mac_Files.mm
+++ b/modules/juce_core/native/juce_mac_Files.mm
@@ -419,7 +419,7 @@ bool Process::openDocument (const String& fileName, const String& parameters)
 
             NSMutableDictionary* dict = [[[NSMutableDictionary alloc] init] autorelease];
             [dict setObject: paramArray
-                     forKey: NSWorkspaceLaunchConfigurationArguments];
+                     forKey: nsStringLiteral ("NSWorkspaceLaunchConfigurationArguments")];
 
             return [workspace launchApplicationAtURL: filenameAsURL
                                              options: NSWorkspaceLaunchDefault | NSWorkspaceLaunchNewInstance