Bravo FAQ: Common Attachments

by Sam C. Chan

First Published: 8/15/05
Last Revised: 10/2/06

What are the commonly acceptable attachment file formats?

You're expected to have the capabilities to handle (view, maybe even edit) the commonly used information interchange data file formats. Anything else should be considered inappropriate to send as attachments. Here's a Quick Reference List:

.pdf   Adobe Acrobat
.mdi   MS Document Imaging (rapidly gaining popularity, with very nice features)
.txt   plain text
.csv   common delimited values (tabular text)
.htm/.html   web page
.rtf   rich text format
.doc   MS Word (viewer available)
.xls   MS Excel (viewer available)
.ppt/.pps   MS Powerpoint  (viewer available)
.vsd   Visio Drawing (viewer available)

.zip   compressed folder
.cab  cabinet file (common for software distribution)
.png (portable network graphic)
.bmp (generally too bulky)

.wma  WMP audio
.wmv  WMP video
.mp3  most common audio
.mov  Quicktime video
.mpg/.mpeg  MPEG video
.swf   Shockwave/Flash
.mid   MIDI musical instrument notes recording file

If you send someone a file in other format, it's very likely that they will not be able to open it, unless they happen to have the same program you used to create it. All of the file formats above have freely downloadable readers/viewers available for all popular operating system platforms, for those who do not have the necessary programs.

Notably missing from the list above:
  • Microsoft Publisher
  • Microsoft Works
  • Microsoft Picture-It
  • Any database (including Access)
  • Printshop
  • Photoshop
  • Encapsulated Postscript (.eps)
(These programs are quite popular but far from being common or standards, thus considered UNACCEPTABLE for general  attachment, as you cannot expect others to be able to handle them. Special arrangements are required. Consider exporting to common formats.)

Notes: With media files, compatibility is more complicated. Being able to handle a certain file extension is not guarantee that the recipient can play your file. For example, they might be able to open your file in a .mpg "container" format. Their player program might still complain about lacking the required codec (coder-decoder) to interpret the content. It must be download & installed within the particular media player used.

File Types BANNED by Outlook 2000/XP/2003/2007:
(The following are considered potentially DANGEROUS. Most IT-controlled companies have additional restrictions. Beware that circumventing such bans via technical means, without obtaining proper authorization could violate the sender/recipient's employment contract.)

.ade Access Project Extension (Microsoft)
.adp Access Project (Microsoft)
.app Executable Application
.asp Active Server Page
.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
.com Command
.cpl Windows Control Panel Extension (Microsoft)
.crt Certificate File
.csh csh Script
.exe Executable File
.fxp FoxPro Compiled Source (Microsoft)
.hlp Windows Help File
.hta Hypertext Application
.inf Information or Setup File
.ins IIS Internet Communications Settings (Microsoft)
.isp IIS Internet Service Provider Settings (Microsoft)
.its Internet Document Set, Internation Translation
.js JavaScript Source Code
.jse JScript Encoded Script File
.ksh UNIX Shell Script
.lnk Windows Shortcut File
.mad Access Module Shortcut (Microsoft)
.maf Access (Microsoft)
.mag Access Diagram Shortcut (Microsoft)
.mam Access Macro Shortcut (Microsoft)
.maq Access Query Shortcut (Microsoft)
.mar Access Report Shortcut (Microsoft)
.mas Access Stored Procedures (Microsoft)
.mat Access Table Shortcut (Microsoft)
.mau Media Attachment Unit
.mav Access View Shortcut (Microsoft)
.maw Access Data Access Page (Microsoft)
.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 Wizard Template (Microsoft)
.msc Microsoft Management Console Snap-in Control File (Microsoft)
.msi Windows Installer File (Microsoft)
.msp Windows Installer Patch
.mst Windows SDK Setup Transform Script
.ops Office Profile Settings File
.pcd Visual Test (Microsoft)
.pif Windows Program Information File (Microsoft)
.prf Windows System File
.prg Program File
.pst MS Exchange Address Book File, Outlook Personal Folder File (Microsoft)
.reg Registration Information/Key for W95/98, Registry Data File
.scf Windows Explorer Command
.scr Windows Screen Saver
.sct Windows Script Component, Foxpro Screen (Microsoft)
.shb Windows Shortcut into a Document
.shs Shell Scrap Object File
.tmp Temporary File/Folder
.url Internet Location
.vb VBScript File or Any VisualBasic Source
.vbe VBScript Encoded Script File
.vbs VBScript Script File, Visual Basic for Applications Script
.vsmacros Visual Studio .NET Binary-based Macro Project (Microsoft)
.vss Visio Stencil (Microsoft)
.vst Visio Template (Microsoft)
.vsw Visio Workspace File (Microsoft)
.ws Windows Script File
.wsc Windows Script Component
.wsf Windows Script File
.wsh Windows Script Host Settings File

See also:

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