Microsoft has just banned additional file types including Java, Python, and PowerShell 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.
Note: If you're using a Microsoft Exchange account, your email server administrator can unblock certain file types. Contact your administrator for more assistance.
The List. New file types are highlighted in Yellow:
| Extension | File type | Extension | File type |
| .ade | Access Project Extension (Microsoft) | .msh2 | Microsoft Shell |
| .adp | Access Project (Microsoft) | .msh2xml | Microsoft Shell |
| .app | Executable Application | .mshxml | Microsoft Shell |
| .appcontent-ms | Third Party Software Exploits | .msi | Windows Installer File (Microsoft) |
| .asp | Active Server Page | .msp | Windows Installer Update |
| .bas | BASIC Source Code | .mst | Windows SDK Setup Transform Script |
| .bat | Batch Processing | .msu | Windows Update file |
| .cer | Internet Security Certificate File | .ops | Office Profile Settings File |
| .chm | Compiled HTML Help | .osd | Open Software Description |
| .cmd | DOS CP/M Command File, Command File for Windows NT | .pcd | Visual Test (Microsoft) |
| .cnt | Microsoft Help Workshop Application | .pif | Windows Program Information File (Microsoft) |
| .com | Command | .pl | Perl script |
| .cpl | Windows Control Panel Extension (Microsoft) | .plg | Developer Studio Build Log |
| .crt | Certificate File | .prf | Windows System File |
| .csh | csh Script | .prg | Program File |
| .der | DER Encoded X509 Certificate File | .printerexport | Printer backup file |
| .diagcab | Microsoft Support diagnostic tools | .ps1 | Windows PowerShell |
| .exe | Executable File | .ps1xml | Windows PowerShell |
| .fxp | FoxPro Compiled Source (Microsoft) | .ps2 | Windows PowerShell |
| .gadget | Windows Vista gadget | .ps2xml | Windows PowerShell |
| .grp | Microsoft program group | .psc1 | Windows PowerShell |
| .hlp | Windows Help File | .psc2 | Windows PowerShell |
| .hpj | AppWizard Help project | .psd1 | Windows PowerShell |
| .hta | Hypertext Application | .psdm1 | Windows PowerShell |
| .inf | Information or Setup File | .psl | Power Shell Files |
| .ins | IIS Internet Communications Settings (Microsoft) | .pst | MS Exchange Address Book File, Outlook Personal Folder File (Microsoft) |
| .isp | IIS Internet Service Provider Settings (Microsoft) | .pyc | Python Files |
| .its | Internet Document Set, Internet Translation | .pyo | Python Files |
| .jar | Java Archive | .pyw | Python Files |
| .jnlp | Java Network Launch Protocol | .pyz | Python Files |
| .js | JavaScript Source Code | .pyzx | Python Files |
| .jse | JScript Encoded Script File | .reg | Registration Information/Key for W95/98, Registry Data File |
| .ksh | UNIX Shell Script | .scf | Windows Explorer Command |
| .lnk | Windows Shortcut File | .scr | Windows Screen Saver |
| .mad | Access Module Shortcut (Microsoft) | .sct | Windows Script Component, Foxpro Screen (Microsoft) |
| .maf | Access (Microsoft) | .settingcontent-ms | Third Party Software Exploits |
| .mag | Access Diagram Shortcut (Microsoft) | .shb | Windows Shortcut into a Document |
| .mam | Access Macro Shortcut (Microsoft) | .shs | Shell Scrap Object File |
| .maq | Access Query Shortcut (Microsoft) | .theme | Desktop theme file settings |
| .mar | Access Report Shortcut (Microsoft) | .tmp | Temporary File/Folder |
| .mas | Access Stored Procedures (Microsoft) | .url | Internet Location |
| .mat | Access Table Shortcut (Microsoft) | .vb | VBScript File or Any Visual Basic Source |
| .mau | Media Attachment Unit | .vbe | VBScript Encoded Script File |
| .mav | Access View Shortcut (Microsoft) | .vbp | Visual Basic project file |
| .maw | Access Data Access Page (Microsoft) | .vbs | VBScript Script File, Visual Basic for Applications Script |
| .mcf | Media Container Format | .vsmacros | Visual Studio .NET Binary-based Macro Project (Microsoft) |
| .mda | Access Add-in (Microsoft), MDA Access 2 Workgroup (Microsoft) | .vsw | Visio Workspace File (Microsoft) |
| .mdb | Access Application (Microsoft), MDB Access Database (Microsoft) | .webpnp | Internet printing file |
| .mde | Access MDE Database File (Microsoft) | .website | Pinned site shortcut from Internet Explorer |
| .mdt | Access Add-in Data (Microsoft) | .ws | Windows Script File |
| .mdw | Access Workgroup Information (Microsoft) | .wsc | Windows Script Component |
| .mdz | Access Wizard Template (Microsoft) | .wsf | Windows Script File |
| .msc | Microsoft Management Console Snap-in Control File (Microsoft) | .wsh | Windows Script Host Settings File |
| .msh | Microsoft Shell | .xbap | Browser applications |
| .msh1 | Microsoft Shell | .xll | Excel add-in |
| .msh1xml | Microsoft Shell | .xnk | Exchange Public Folder Shortcut |