Crash Almost Any OS X App By Typing These Specific Characters

Crash OS X Character String

An odd bug in OS X causes nearly any application to crash by typing in a short string of characters, according to a bug report published last Thursday and brought to our attention by tech site Neowin. Typing the world “File” (with a capital F), a colon, and three forward slashes will crash most apps on OS X Mountain Lion.

We had to log into our site’s backend via Windows to type the following string of characters because doing so on OS X crashed both our text editor and the Web browser we use to upload articles. Here it is:


It has been suggested that the bug is linked to OS X’s built-in spellchecker, but the crash occurs in locations that are not spellchecked, such as Chrome’s address bar. We’ve tested and verified that the bug occurs in TextEdit, Calendar, and even Final Cut Pro X. Third-party apps such as Chrome and Byword are also affected.

Although Safari crashes if we type the phrase into a text box on a Web page, it surprisingly did not crash when we typed it in to Safari’s address bar, although we’ve read reports from some users that claim that even the Safari address bar was affected for them.

The bug occurs on all versions of OS X 10.8 Mountain Lion, including the latest prerelease build of 10.8.3. Macs natively running previous versions of OS X were not available for testing but none our OS X virtual machines dating back to 10.5 Leopard were affected when virtualized by VMware Fusion.

Apple has been notified of the bug and should hopefully have a fix soon. Although the string of characters is not a common one that many users are likely to type, it may be cause for mischief or a point of attack by those coding software with malicious intent.

Those who wish to attempt to recreate the bug are free to do so by typing the phrase into nearly any OS X application. The only recommendation is to save any important documents or files first, as our testing shows that few apps stand a chance against crashing.