Bush hid the facts

Bush hid the facts is a common name for a bug present in some Microsoft Windows applications, which causes a file of text encoded in ASCII or its superset (such as in a Windows code page) to be interpreted as if it were UTF-16LE, resulting in mojibake. When "Bush hid the facts" (without newline or quotes) is put in a new (pre-Vista) Notepad document and saved, closed, and reopened, the nonsensical Chinese characters "畂桳栠摩琠敨映捡獴" (pinyin: Liù bèn rěn mó tiǎn tǒu yìng jiǎn měng) appear instead.

While "Bush hid the facts" is the sentence most commonly presented on the Internet to induce the error, the bug can be triggered by many sentences with characters and spaces in a particular order so that the bytes match the UTF-16LE encoding of valid (if nonsensical) Chinese Unicode characters. Other popular strings are "this app can break", "acre vai pra globo" (Portuguese for "Acre goes to Rede Globo"), and "aaaa aaa aaa aaaaa". The bug is triggered even by the text "a ".

The bug occurs when the string is passed to the Win32 charset detection function IsTextUnicode with no other characters. IsTextUnicode sees what it thinks is valid UTF-16LE Chinese and returns true, and the application then incorrectly interprets the text as UTF-16LE.