Microsoft Office 365 Outlook Email Quarantined File Extensions

One of the most common ways of transmitting computer viruses is through file attachments. To help protect you and your recipients against computer viruses, Outlook blocks the sending and receiving of certain types of files (such as .exe and certain database files) as attachments. If you need to send one of these file types to an email recipient, we recommend using OneDrive and sending the recipient a link to the file instead.

If you attempt to email a blocked file type you will receive an email similar to what is shown below.

----Sample-Message----

From: Postmaster

Sent: Tuesday, February 16, 2021 11:16 AM

To: email@microsoftoffice365.com

Subject: Undeliverable message

This message was created automatically by mail delivery software. Your email message was not delivered to the intended recipients because malware was detected.

— Additional Information ---:

Subject: Your Email Subject Here

Sender: you@salisbury.edu

Time received: 2/16/2021 4:15:54 PM

Message ID:<######>

Detections found:

filename.filetype

File types blocked in Outlook

File name extension	File type
.ace
.ade	Access Project Extension (Microsoft)
.adp	Access Project (Microsoft)
.app	Executable Application
.application
.asp	Active Server Page
.aspx	Active Server Page Extended
.asx	ASF Redirector file
.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 Help Workshop Application
.com	Command
.cpl	Windows Control Panel Extension (Microsoft)
.crt	Certificate File
.csh	csh Script
.der	DER Encoded X509 Certificate File
.diagcab	Microsoft Support diagnostic tools
.docm
.dotm
.eml
.exe	Executable File
.fxp	FoxPro Compiled Source (Microsoft)
.gadget	Windows Vista gadget
.grp	Microsoft program group
.gz
.hlp	Windows Help File
.hpj	AppWizard Help project
.hta	Hypertext Application
.htc	HTML component file
.htm
.html
.inf	Information or Setup File
.ins	IIS Internet Communications 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	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)
.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 Wizard Template (Microsoft)
.msc	Microsoft Management Console Snap-in Control File (Microsoft)
.msh	Microsoft Shell
.msh1	Microsoft Shell
.msh2	Microsoft Shell
.mshxml	Microsoft Shell
.msh1xml	Microsoft Shell
.msh2xml	Microsoft Shell
.msi	Windows Installer File (Microsoft)
.msp	Windows Installer Update
.mst	Windows SDK Setup Transform Script
.msu	Windows Update file
.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
.potm
.ppam
.pptm
.potm
.prf	Windows System File
.prg	Program File
.printerexport	Printer backup file
.ps1	Windows PowerShell
.ps1xml	Windows PowerShell
.ps2	Windows PowerShell
.ps2xml	Windows PowerShell
.psc1	Windows PowerShell
.psc2	Windows PowerShell
.psd1	Windows PowerShell
.psdm1	Windows PowerShell
.pst	MS Exchange Address Book File, Outlook Personal Folder File (Microsoft)
.py	Python script
.pyc	Python script
.pyo	Python script
.pyw	Python script
.pyz	Python script
.pyzw	Python script
.rar
.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
.sldm
.theme	Desktop theme file settings
.tmp	Temporary File/Folder
.url	Internet Location
.vb	VBScript File or Any Visual Basic Source
.vbe	VBScript Encoded Script File
.vbp	Visual Basic project file
.vbs	VBScript Script File, Visual Basic for Applications Script
.vhd	Virtual Hard Disk
.vhdx	Virtual Hard Disk Extended
.vsmacros	Visual Studio .NET Binary-based Macro Project (Microsoft)
.vsw	Visio Workspace File (Microsoft)
.webpnp	Internet printing file
.website	Pinned site shortcut from Internet Explorer
.xlam
.xltm
.xlsm
.ws	Windows Script File
.wsc	Windows Script Component
.wsf	Windows Script File
.wsh	Windows Script Host Settings File
.xbap	Browser applications
.xll	Excel add-in
.xnk	Exchange Public Folder Shortcut