OSStatus.com (via Seth Willits) is a great resource for quickly looking up error codes. It supports not only the traditional OSStatus error codes, but also NSError codes from NSCocoaErrorDomain, kCFErrorDomainCFNetwork, NSPOSIXErrorDomain (errno.h), etc. Update (2015-10-04): Marco Masser: This [LaunchBar] action uses osstatus.com to look up information about error codes on Apple’s platforms. This is useful … Continue reading OSStatus.com