You Can Crash OS X Mountain Lion Apps Just By Typing These Letters

Given the complexity of modern operating systems, bugs are to be expected. Some are obvious, but inconsequential, while others are catastrophic, though rare. A recently found bug with OS X Mountain Lion falls into the latter category, causing an app that supports text input to crash, simply by typing in a few letters.

The letters in questions? Here you go:


You can trigger the crash yourself by opening up TextEdit and whacking in the fateful phrase, or almost any app that supports inputting text. This includes parts of the operating system, such as Spotlight, which will act bizarrely if faced with the text.

You can read some more details in this bug report over on Open Radar. It theorises the bug is due to the spell checker, but going through the comments (and looking at the crash report itself), it may be related to data detectors. If you were hoping disabling the spell checker would help, it doesn't, at least going by other users posting on the report.

The bug appears to only affect OS X Mountain Lion. I tried to replicate the bug on a MacBook Air running OS X 10.7.5 (Lion) and was greeted by soothing stability in both TextEdit and Word.

If you're running any recent flavour of OS X, give it a go and let us know. Just make sure you're not doing anything work critical at the time...

[Open Radar, via @Matt_Phipps]

Image: Tambako The Jaguar / Flickr, licensed under Creative Commons 2.0



    Plugged it into Text edit on 10.8.2 and it crashed right away. Might put it into other things to see what it does.

    Plugged it in StickyNotes, it crashed too. Typing it in Safari also caused a crash.

    Last edited 03/02/13 11:42 am

    Strangely, it's actually case-sensitive, so typing "file:///" does nothing, but typing, well, with a capital "F" will crash the app you're typing in.

    Disgruntled employ drops random if statement into code on last day for Lols?

      Nah, as the article says, it's probably some data detector, the kind of thing meant to detect phone numbers and the like and highlight them as such. Perhaps there is one that interacts with the file system, and it recognises the beginning of a file URI, resulting in a URI that looks like "File:///File:///" in the system, and thus it breaks, because no one thought that could happen.

    crashes chrome too, type in address bar and push enter

    typing it into spotlight search causes the entire menu bar to crash and reset itself

    Crashes my Windows 7 x64 pc too

      Where are you typing it?

        Don't feed the troll.

          Ah I considered that matter, but I thought I'd give him the benefit of the doubt.

            Sorry Jacrench, didn't mean to fool you. Actually thought it would be obvious sarcasm :)

    Typed it in Firefox and it doesn't crash (search and address bar).

    Chrome, and Windows systems don't mind this line...

    Chrome responde:

    This web page has not been found
    No web page was found for the web address: file:///
    Error 6 (net::ERR_FILE_NOT_FOUND): The file or directory could not be found.

    Stop Trolling...

    Safari handles it fine - in fact it autocompletes some html files that I was working on locally: file:///Users/me/Desktop/blah/index.html TextEdit crashed straight away though.

    Typed it into chrome, didn't even press enter, it instantly crashed

    Wasn't this whole context thing a basis of one of Apple's pursuits against Android? And yet they can't get it right? Wow...

      nah, this is a URI thing, the data detector stuff was about recognising patterns like phone numbers, addresses, emails, etc.

    lol, created a folder on my desktop called File:/// and the whole OS locked up, lololol.

    It doesn't do any damage putting it in the password field. :( that would be an awesome prank.

    It crashed the bug submitting textbox too after it crashed something else beforehand.

    This is a hoax, my Mac obsessed friends tell me that OSX is just perfect and never has any faults, never crashes and (here we go), 'just works'.

      'Just works' where 'File:///' == "initiate emergency application shut-down"

    I've typed it into as many apps as I can find, the only thing I've been able to do is cause spotlight to reindex my disk.

    I've tried the following combos (this text box was populated by FFox 18.0.1 on MacOS 10.8.2

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