An error message is information displayed when an unforeseen problem occurs, usually on a

computer A computer is a machine that can be programmed to Execution (computing), carry out sequences of arithmetic or logical operations (computation) automatically. Modern digital electronic computers can perform generic sets of operations known as C ...

or other device. On modern operating systems with graphical user interfaces, error messages are often displayed using dialog boxes. Error messages are used when user intervention is required, to indicate that a desired operation has failed, or to relay important warnings (such as warning a computer user that they are almost out of

hard disk A hard disk drive (HDD), hard disk, hard drive, or fixed disk is an electro-mechanical data storage device that stores and retrieves digital data using magnetic storage with one or more rigid rapidly rotating platters coated with magnet ...

space). Error messages are seen widely throughout computing, and are part of every operating system or

computer hardware Computer hardware includes the physical parts of a computer, such as the computer case, case, central processing unit (CPU), Random-access memory, random access memory (RAM), Computer monitor, monitor, Computer mouse, mouse, Computer keyboard, ...

device. Proper design of error messages is an important topic in

usability Usability can be described as the capacity of a system to provide a condition for its users to perform the tasks safely, effectively, and efficiently while enjoying the experience. In software engineering, usability is the degree to which a soft ...

and other fields of human–computer interaction.

Common error messages

The following error messages are commonly seen by modern computer users: ;Access denied :This error occurs if the user doesn't have privileges to a file, or if it has been

locked Lock(s) may refer to: Common meanings *Lock and key, a mechanical device used to secure items of importance *Lock (water navigation), a device for boats to transit between different levels of water, as in a canal Arts and entertainment * ''Lock ...

by some program or user. ;Device not ready :This error most often occurs when there is no

floppy disk A floppy disk or floppy diskette (casually referred to as a floppy, or a diskette) is an obsolescent type of disk storage composed of a thin and flexible disk of a magnetic storage medium in a square or nearly square plastic enclosure lined w ...

(or a bad disk) in the disk drive and the system tries to perform tasks involving this disk. ;File not found :The file concerned may have been damaged, moved, deleted, or a bug may have caused the error. Alternatively, the file simply might not exist, or the user has mistyped its name. This is most commonly seen on the internet with outdated links to web pages that no longer exist. On a local computer, this is more frequent on

command line interface A command-line interpreter or command-line processor uses a command-line interface (CLI) to receive commands from a user in the form of lines of text. This provides a means of setting parameters for the environment, invoking executables and pro ...

s than on graphical user interfaces where files are presented iconically and users do not type file names. ;Low Disk Space :This error occurs when the hard drive is (nearly) full. To fix this, the user should close some programs (to free swap file usage) and delete some files (normally temporary files, or other files after they have been backed up), or get a bigger hard drive. ;Out of memory :This error occurs when the system has run out of memory or tries to load a file too large to store in RAM. The fix is to close some programs or install more memory. ; rogram namehas stopped working. :This message and similar ones are displayed by several operating systems when program causes a general protection fault or invalid page fault.

Notable error messages

Abort, Retry, Fail? "Abort, Retry, Fail?" (or "Abort, Retry, Ignore?") is an error message found in DOS operating systems, which prompts the end-user for a course of action to follow. Although welcomed by some, the message also has been cited as an example of poo ...

- A notoriously confusing error message seen in MS-DOS Error Message Example vbs

* Bad command or file name - Another notoriously common and confusing error message seen in MS-DOS * The Blue Screen of Death - On Microsoft Windows and ReactOS operating systems, this screen appears when Windows or ReactOS can no longer run because of a severe error. It is roughly analogous to a

kernel panic A kernel panic (sometimes abbreviated as KP) is a safety measure taken by an operating system's kernel upon detecting an internal fatal error in which either it is unable to safely recover or continuing to run the system would have a higher ...

on Linux, Unix, or macOS. *

Can't extend In computing, file system fragmentation, sometimes called file system aging, is the tendency of a file system to lay out the contents of files non-continuously to allow in-place modification of their contents. It is a special case of data fragmen ...

- an error message from

Acorn The acorn, or oaknut, is the nut of the oaks and their close relatives (genera ''Quercus'' and '' Lithocarpus'', in the family Fagaceae). It usually contains one seed (occasionally two seeds), enclosed in a tough, leathery shell, and borne ...

DFS. DFS stores files in non-fragmented contiguous disk space, this error is caused when trying to extend an open random-access file into space that is already occupied by another file. *

Guru Meditation Guru Meditation started as an error notice displayed by the Amiga computer when it crashes. It is now also used by Varnish, a software component used by many content-heavy websites. This has led to many internet users seeing a "Guru Meditation ...

- an error message from the Commodore Amiga, roughly analogous to a kernel panic or BSOD, also adopted by more recent products such as VirtualBox. * HTTP 404 - A file not found error seen on the World Wide Web, usually resulting from a link to a page that has been moved or deleted, or a mistyped URL * lp0 on fire - A Unix warning that the printer may be "on fire", literally or not *

Not a typewriter In computing, "Not a typewriter" or ENOTTY is an error code defined in the errno.h found on many Unix systems. This code is now used to indicate that an invalid ioctl (input/output control) number was specified in an ioctl system call. Details ...

- A Unix error message that is confusing due to its now obsolete use of the word " typewriter", and which is sometimes output when the nature of the error is seemingly entirely different *

PC LOAD LETTER PC LOAD LETTER is a printer error message that has entered popular culture as a technology meme referring to a confusing or inappropriate error message. The error message's vagueness was mocked in the 1999 comedy film ''Office Space''. The messa ...

- An error on several HP laser printers that simply asked the user to add "Letter" size paper in a confusing way * SYNTAX ERROR - Seen on many computer systems when the received instructions are in a format they don't understand *

HTTP 504 This is a list of Hypertext Transfer Protocol (HTTP) response status codes. Status codes are issued by a server in response to a client's request made to the server. It includes codes from IETF Request for Comments (RFCs), other specifications, ...

- An error found on the World Wide Web stating that a gateway timeout occurred in the internet link. * Error 1603 - An error that states that a problem during installation of a computer program, this error particularly occurs on Windows computer systems. * <application name> has stopped - An error message commonly found on

Android Android may refer to: Science and technology * Android (robot), a humanoid robot or synthetic organism designed to imitate a human * Android (operating system), Google's mobile operating system ** Bugdroid, a Google mascot sometimes referred to ...

devices, which states a current running application unexpectedly stops working or crashes. * Success - one of the error messages (in this instance, POSIX) that occurs when the program has detected an error condition, yet the actual error message printing routine relies on C library to print the error reported by the operating system (in this case,

errno.h errno.h is a header file in the standard library of the C programming language. It defines macros for reporting and retrieving error conditions using the symbol errno (short for "error number").International Standard for Programming Language C ...

), while the underlying system calls have succeeded and report no errors (in this case,

errno 
 0

). This is a form of sloppy error handling that is particularly confusing for the user. * onnection Time Out Error Mac- Error occurs on Mac systems when it takes more time to connect wireless networks.

Fail pets

With the rise of Web 2.0 services such as Twitter, end-user facing error messages such as HTTP 404 and

HTTP 500 This is a list of Hypertext Transfer Protocol (HTTP) response status codes. Status codes are issued by a server in response to a client's request made to the server. It includes codes from IETF Request for Comments (RFCs), other specifications, ...

started to be displayed with whimsical characters, termed Fail Pets or Error Mascots. The term "Fail Pet" was coined, or at least first used in print, by Mozilla Engineer Fred Wenzel in a post on his blog entitled "Why Wikipedia might need a fail-pet — and why Mozilla does not." Dr. Sean Rintel argues that error messages are a critical strategic moment in

brand awareness Brand awareness is the extent to which customers are able to recall or recognize a brand under different conditions. Brand awareness is one of two dimensions from brand knowledge, an associative network memory model. Brand awareness is a key consi ...

and loyalty. Fail pets are of interest to marketers because they can result in brand recognition (especially through earned media). "However, that same recognition carries the danger of highlighting service failure." The most famous fail pet is Twitter's

Fail Whale Twitter is an online social media and social networking service owned and operated by American company Twitter, Inc., on which users post and interact with 280-character-long messages known as "tweets". Registered users can post, like, and ...

(see Twitter service outages). Other fail pets include: *

Ars Technica ''Ars Technica'' is a website covering news and opinions in technology, science, politics, and society, created by Ken Fisher and Jon Stokes in 1998. It publishes news, reviews, and guides on issues such as computer hardware and software, sci ...

: Moon Shark (March 3, 2013) * FarmVille on Facebook: Sad cow. * GitHub: Octocat * Google: Broken robot (March 2, 2011) * iCloud: Cloud with Apple System 7 emoticon-style face and a magnifying glass * Macintosh:

Sad Mac The classic Macintosh startup sequence includes hardware tests which may trigger the startup chime, Happy Mac, Sad Mac, and Chimes of Death. On Macs running macOS Big Sur or later the startup sound is enabled by default, but can be disabled by ...

Palliser Furniture Palliser Furniture is a family-owned furniture manufacturing company headquartered in Winnipeg, Manitoba, Canada. , the company was the largest manufacturer of made-to-order leather furniture in North America.Tumblr: Tumbeasts (January 25, 2011) * Twitter: Fail Whale / Twitter Robot (July 30, 2008) * YouTube: Televisions (on main site), light static inside video window (embedded video) *

Cartoon Network Cartoon Network (often abbreviated as CN) is an American cable television channel owned by Warner Bros. Discovery. It is a part of The Cartoon Network, Inc., a division that also has the broadcasting and production activities of Boomerang, Car ...

: BMO sia Domo *

Google Chrome Google Chrome is a cross-platform web browser developed by Google. It was first released in 2008 for Microsoft Windows, built with free software components from Apple WebKit and Mozilla Firefox. Versions were later released for Linux, macOS ...

: T-Rex * Patreon:

Red fox The red fox (''Vulpes vulpes'') is the largest of the true foxes and one of the most widely distributed members of the Order (biology), order Carnivora, being present across the entire Northern Hemisphere including most of North America, Europe ...

with a helmet floating in space * VK: Sad Vkontakte dog * Scratch
Giga
scratching his head

Message format

The form that error messages take varies between operating systems and programs. Error messages on hardware devices, like computer peripherals, may take the form of dedicated lights indicating an error condition, a brief code that needs to be interpreted using a look-up sheet or a manual, or via a more detailed message on a display. On computers, error messages may take the form of text printed to a console, or they may be presented as part of a graphical user interface. Error messages are often presented as a dialog box, which makes them cause a following mode error in the user interaction. In many cases the original error can be avoided by error prevention techniques. Instead of raising an error message the system design should have avoided the conditions that caused the error. While various graphical user interfaces have different conventions for displaying error messages, several techniques have become common: * A dialog box, or pop-up message, appears in a window on the screen, blocking further interaction with the computer until it is acknowledged. On Mac OS X, sheets are a form of dialog box that are attached to a specific window. * Notification icons appear to notify a user about a condition without interrupting their work. On Windows, notification icons appear in the System Tray. On Mac OS X, notification icons may appear in the menu bar, or may take the form of an application's icon "bouncing" in the Dock. The

GNOME A gnome is a mythological creature and diminutive spirit in Renaissance magic and alchemy, first introduced by Paracelsus in the 16th century and later adopted by more recent authors including those of modern fantasy literature. Its characte ...

user interface for Unix systems can display notification icons in a panel. * Minor errors may be displayed in a status bar, a small portion of an application's window that can display brief messages to the user. The three main factors that influence the design of error messages are technical limitations, the amount of information to be presented, and what kind of user input is required. Some systems have technical limitations that may constrain the amount of information an error message can contain. For example, a printer with a sixteen-character alphanumeric display can only show a very limited amount of information at once, so it may need to display very terse error messages. Even with computer monitors, the programmer must consider the smallest monitor that a user might reasonably use, and ensure that any error messages will fit on that screen. The nature of the error determines the amount of information required to effectively convey the error message. A complex issue may require a more detailed error message in order to adequately inform the user of the problem.

Security

When designing error messages, software designers should take care to avoid creating security vulnerabilities. The designer should give the user enough information to make an intelligent decision, but not so much information that the user is overwhelmed or confused. Extraneous information may be hidden by default or placed in a separate location. Error message should not expose information that can be exploited by a

cracker Cracker, crackers or The Crackers may refer to: Animals * ''Hamadryas'' (butterfly), or crackers, a genus of brush-footed butterflies * '' Sparodon'', a monotypic genus whose species is sometimes known as "Cracker" Arts and entertainment Films ...

to obtain information that is otherwise difficult to obtain. Examples are

systems A system is a group of interacting or interrelated elements that act according to a set of rules to form a unified whole. A system, surrounded and influenced by its environment, is described by its boundaries, structure and purpose and express ...

which may show either "invalid user" or "invalid password" depending on which is incorrect, and the error page in the

web server A web server is computer software and underlying hardware that accepts requests via HTTP (the network protocol created to distribute web content) or its secure variant HTTPS. A user agent, commonly a web browser or web crawler, initiate ...

IIS 5.0 which provides a complete technical description of the error including a source code fragment.

References

External links

A more useful 404 (A List Apart)Avoid being embarrassed by your error messages (UX Matters)
{{DEFAULTSORT:Error Message Computer errors Human–computer interaction