Blocked files and attachments

The following files and attachments are blocked in Outlook and web access, i.e. they cannot be opened or saved.

Exchange web access

The following are blocked by default in OWA:

BlockedFileTypes

{.vsmacros, .msh2xml, .msh1xml, .diagcab, .ps2xml, .ps1xml, .mshxml, .gadget, .mhtml, .xbap, .psc2, .psc1, .msh2, .msh1, .jnlp, .aspx, .xnk, .xll, .wsh, .wsf,

.wsc, .vsw, .vbs, .vbp, .vbe, .url, .tmp, .shs, .shb, .sct, .scr, .scf, .reg, .pst, .ps2, .ps1, .prg, .prf, .plg, .pif, .pcd, .osd, .ops, .mst, .msp, .msi, .msh

.msc, .mht, .mdz, .mdw, .mdt, .mde, .mdb, .mda, .mcf, .maw, .mav, .mau, .mat, .mas, .mar, .maq, .mam, .mag, .maf, .mad, .lnk, .ksh, .jse, .jar, .its, .isp, .ins

.inf, .htc, .hta, .hpj, .hlp, .grp, .fxp, .exe, .der, .csh, .crt, .cpl, .com, .cnt, .cmd, .chm, .cer, .bat, .bas, .asx, .asp, .app, .adp, .ade, .ws, .vb, .pl, .js}

BlockedMimeTypes

{application/x-javascript, application/javascript, application/msaccess, x-internet-signup, text/javascript, application/prg, application/hta, text/scriplet}

appref-ms - Windows ClickOnce, .cdxml - PowerShell cmdlet definition, .pssc - PowerShell session configuration, .udl - Microsoft Data Link, used by Microsoft Data Access Components (MDAC), .wsb - Windows sandbox, .vhd, .vhdx, .py, .pyc, .pyo, .pyw, .pyz, .pyzw

File types blocked by Outlook:

.ADE Access project extension (Microsoft)
.ADP Access project (Microsoft)
.APP Executable application
.ASP Active Server Pages
.BAS BASIC source code
.BAT Batch processing
.CER Internet security certificate file
.CHM Compiled HTML Help
.CMD DOS CP/M command file, command file for Windows NT
.CNT Microsoft Workshop Application Help
.COM Command
.CPL Windows Control Panel Option (Microsoft)
.CRT Certificate File
.CSH CSH script
.DER DER-encoded X509 certificate file
.EXE Executable file
.FXP Compiled FoxPro source (Microsoft)
.GADGET Windows Vista gadget
.GRP Microsoft program group
.HLP Windows help file
.HPJ Project AppWizard Help
.HTA Hypertext Application
.INF Information or Setup File
.INS IIS Internet Communication Settings (Microsoft)
.ISP IIS Internet Service Provider Settings (Microsoft)
.ITS Internet Document Set, Internet Translation
.JAR Java archive
.jnlp Java Network Launch Protocol
.JS JavaScript source code
.JSE Encrypted JScript script file
.KSH UNIX shell script
.LNK Windows shortcut file
.MAD Access module shortcut (Microsoft)
.MAF Access (Microsoft)
.MAG Access graph shortcut (Microsoft)
.MAM Access macro shortcut (Microsoft)
.MAQ Access query shortcut (Microsoft)
.MAR Access report link (Microsoft)
.MAS Access stored procedures (Microsoft)
.MAT Access table link (Microsoft)
.MAU Media Attachment Unit
.MAV Access view link (Microsoft)
.MAW Access Data Access Page (Microsoft)
.MCF Media Container Format
.MDA Access Add-In (Microsoft), MDA Access 2 Workgroup (Microsoft)
.MDB Access Application (Microsoft), MDB Access Database (Microsoft)
.MDE Access MDE database file (Microsoft)
.MDT Access add-in data (Microsoft)
.MDW Access workgroup information (Microsoft)
.MDZ Access database wizard (Microsoft)
.MSC Control File (Microsoft) for the Microsoft Management Console snap-in
.MSH Microsoft Shell
.MSH1
.MSH2
.MSHXML
.MSH1XML
.MSH2XML
.MSI Windows Installer Package (Microsoft)
.MSP Update for Windows Installation Service
.MST Windows SDK Setup Transformation Script
.OPS Office Profile Settings File
.OSD Open Software Description
.PCD Visual Test (Microsoft)
.PIF Windows Program Information File (Microsoft)
.PL Perl Script
.PLG Developer Studio build log
.PRF Windows system file
.PRG program file
.PS1 Windows PowerShell
.PS1XML
.PS2
.PS2XML
.PSC1
.PSC2
.PST MS Exchange address book file, personal folder file in Outlook (Microsoft)
.REG Registry information/key for Windows 95/Windows 98, registry data file
.SCF Windows Explorer command
.SCR Windows screen saver
.SCT Windows script component, Foxpro display (Microsoft)
.SHB Windows document shortcut
.SHS Shell Scrap object file
.TMP Temporary file/temporary folder
.URL Internet location
.VB VBScript file or any Visual Basic source
.VBE Encrypted VBScript file
.vbp Visual Basic project file
.VBS VBScript script file, VBA script
.VSMACROS Binary-based Visual Studio .NET macro project (Microsoft)
.VSW Visio workspace file (Microsoft)
.WS Windows script file
.WSC Windows script component
.WSF
.WSH Windows Script Host settings file
.XBAP Browser applications
.XLL Excel add-ins
.XNK Link to public folder in Exchange