PC LOAD LETTER
The actual meaning of the message is convoluted: "PC" is a two-character abbreviation that stands for "paper cassette", the tray which holds blank paper for the printer to use. These two-character codes are a legacy feature carried over from the first LaserJet printers, which could only use a two-character display for all printer status and error messages.
"Load", in this context, is an instruction to refill the paper tray. "Letter" is the standard paper size used in the United States and Canada. Thus, the error is instructing the user to refill the paper tray with letter-sized paper. A variant is "PC LOAD LEGAL", meaning that the printer needs more legal size paper.
The non-intuitive message confuses people for several reasons. The abbreviation "PC" is misleading because it is widely understood — especially in the context of electronic office equipment — to mean "personal computer", suggesting to many that the problem lies in the computer, not the printer. The word "LOAD" is also ambiguous, as it can also refer to the transfer of electronic data between disk and memory. Furthermore, the word "LETTER" is only associated with paper size in the US, Canada and some Latin American countries; A4 is the standard size used in the rest of the world. Thus, users encountering this message may believe that they are being instructed to transfer the data or content of their typed letter (as in correspondence) to the printer, even though they have already sent the job to the printer. (The printer could not "know" that they had anything they wanted to print if the print job had not already been initiated from the computer, however.)
Older LaserJet printers do not automatically resize a page when the page size of a document does not match the paper that is loaded in the printer. When trying to print a document whose paper size is set to "letter" on A4-sized paper the message occurs. The error "PC LOAD A4" appears in countries using this paper size. However, as many programs use "letter" as the default format, the confusing message is often encountered by non-American users who are unaware of the recovery procedure (empty print queue and printer buffer or press "Shift/Continue" and in extreme cases, restart printer and repeat). The LaserJet 5 introduced an easy-to-find "GO" button to override the warning message.
In popular culture 
The term was popularized by the comedy film Office Space. Michael Bolton (David Herman), one of the three main characters, reads the error message from the status display on a printer, after which he asks, "PC LOAD LETTER? The fuck does that mean?"  This message appears on the display just after Bolton fills the printer's tray with blank paper. Frustrations such as this lead the main characters of the film to take revenge on the malfunctioning printer by stealing it, taking it to a field and destroying it with a baseball bat.
See also 
- "One of many official Hewlett-Packard technical documents defining PC as a short-form of Paper Cassette". Retrieved March 30, 2007.
- "Instructions for solving printer errors.". Retrieved April 23, 2007.
- Michael Bolton (David Herman) (1999). Video Clip of Scene between Michael Bolton and Printer (Video) (in English). YouTube. Retrieved 28 February 2013.