What are the list of File Extensions can’t be Attached?

Blocked file extensions from attachment
File Extensions Graphical Illustration

What is a file extension?

After naming a file, extensions are used to identify the type of a file. The extensions are added to the filename as a suffix with a dot representation(.) followed by one, two three or four characters. A file may have multiple extensions. Example:file.txt is a file name and .txt is its extension.

Why file extensions are used?

File extensions help an operating system to determine the program in which the file is associated. For example, file extensions starting with .m are often music or video formats such as .mov,.mp3,.mp4. These formats help the operating system to access the correct program quickly in the system.

List of file extensions that can’t be attached:

Some of the file extensions are blocked by default for uploading and downloading because those files may be executable files. Files with curly braces {} are also automatically blocked. The file extensions that are blocked by default are as follows



.adeMicrosoft Access project extension
.adpMicrosoft Access project
.appApplication file
.asaASP declarations file
.ashxASP.NET Web handler file. Web handlers are software modules that handle raw HTTP requests received by ASP.NET.
.asmxASP.NET Web Services source file
.aspActive Server Pages
.basMicrosoft Visual Basic class module
.batBatch file
.cdxCompound index
.cerCertificate file
.chmCompiled HTML Help file
.classJava class file
.cmdMicrosoft Windows NT command script
.comMicrosoft MS-DOS program
.configConfiguration file
.cplControl Panel extension
.crtSecurity certificate
.cshScript file
.dllWindows dynamic link library
.fxpMicrosoft Visual FoxPro compiled program
.hlpHelp file
.htaHTML program
.htrScript file
.htwHTML document
.idaInternet Information Services file
.idcInternet database connector file
.idqInternet data query file
.insInternet Naming Service
.ispInternet Communication settings
.itsInternet Document Set file
.jseJScript Encoded script file
.kshKorn Shell script file
.masMicrosoft Access stored procedure
.mdaMicrosoft Access add-in program
.mdbMicrosoft Access program
.mdeMicrosoft Access MDE database
.mdtMicrosoft Access data file
.mdwMicrosoft Access workgroup
.mdzMicrosoft Access wizard program
.mscMicrosoft Common Console document
.mshMicrosoft Agent script helper
.msh1Microsoft Agent script helper
.msh1xmlMicrosoft Agent script helper
.msh2Microsoft Agent script helper
.msh2xmlMicrosoft Agent script helper
.mshxmlMicrosoft Agent script helper
.msiMicrosoft Windows Installer package
.mspWindows Installer patch package file
.mstVisual Test source files
.opsMicrosoft Office profile settings file
.pcdPhoto CD image or Microsoft Visual Test compiled script
.pifShortcut to MS-DOS program
.prfSystem file
.prgProgram source file
.printerPrinter file
.pstMicrosoft Outlook personal folder file
.regRegistration entries
.remACT! database maintenance file
.scfWindows Explorer command file
.scrScreen saver
.sctScript file
.shbWindows shortcut
.shsShell Scrap object
.shtmHTML file that contains server side directives
.shtmlHTML file that contains server side directives
.soapSimple Object Access Protocol file
.stmHTML file that contains server side directives
.urlUniform Resource Locator (Internet shortcut)
.vbMicrosoft Visual Basic Scripting Edition (Visual Basic Scripting Edition (VBScript)) file
.vbeVBScript Encoded Script file
.vbsVBScript file
.wsWindows Script file
.wscWindows Script Component
.wsfWindows Script file
.wshWindows Script Host settings file


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