When a program unexpectedly quits in OS X, the system will activate the crash reporter that will generate a report that includes the memory backtrace for each thread and other information about the crashed process. This can be used to help troubleshoot the situations or be submitted to developers so erroneous code can be tested and corrected. The crash reporter will by default show the full crash log on screen, but this can be changed to either show just a warning, or never show the crash reporter.
The setting to do this is hidden in the system, but it can be changed by running the following command in the Terminal:
defaults write com.apple.CrashReporter DialogType MODE
In this command, substitute the word "MODE" with one of the following options, to set the crash reporter behavior accordingly:
Developer -- This is the full crash reporter that will show the entire crash log whenever a program unexpectedly quits. This is the default behavior of the crash reporter.
Basic -- This option will show you a warning whenever a program crashes, but will not display the entire crash log.
Server -- This option will not launch the crash reporter and is the default setting for OS X Server, so the system will not launch and keep the crash reporter program open without a server admin desiring it to be.
While the use of the Terminal in this manner will work for all OS X installations, there is an even easier method to access these settings if you have installed Apple's XCode developer tools, which are available for free from the Mac App Store. With the tools installed, go to the /Macintosh HD/Developer/Applications/Utilities/ folder and open the program called "CrashReporterPrefs." In this program you will see the three options for Developer, Basic, and Server.
While these options will change the behavior of the crash reporter, they will not change the way the system generates the crash reports. When a program crashes, a crash report will continue to be created and stored in in the /Logs/CrashReporter/ directory that is either in your user Library folder (for applications launched under your account) or in the global Library folder at the root of the filesystem (for applications that run globally under the root account, such as antivirus tools, and the log-in window).
If you have disabled the crash reporter or set it to the Basic mode and wish to access a crash log, you can do so by opening the Console utility (in the /Applications/Utilities/ folder) and selecting the desired crash report under the "CrashReporter" section. Crash reports should be named with the naming convention "Application Name_Date_Time_Computer.crash" to make them easier to identify.