How to Blocked attachments in Outlook
Share your files safely
If you want to receive a file of a type that is blocked by Outlook, you can ask the sender to either make the file accessible without using Outlook, or make it less likely to be blocked by Outlook. Following are a few safe ways to share files with people you trust.
Use a shared server
You might want to ask the sender to save the attachment to a server or an FTP site that you can access. This can include a secure network share server such as SharePoint. The sender can send you a link to the attachment on the server or FTP site. You can click the link to access the file and save it on your computer.
Use a file compression utility
Using a compression utility, such as WinZip, creates a compressed archive file that has a different file name extension. Outlook does not recognize these file name extensions as potential threats. Therefore, it does not block the new attachment. Many third-party compression utilities are available.
Rename the file
You can request that the sender rename the attachment to use a file name extension that Outlook does not recognize as a threat. For example, an executable file that has the file name extension .exe could be renamed as a Word 2010 file that has a .docx file name extension.
Ask the sender to resend the renamed attachment to you. To save the attachment and rename it to use the original file name extension, do the following:
- Locate the attachment in the email message.
- Right-click the attachment, and then click Copy.
- Right-click the desktop, and then click Paste.
- Right-click the pasted file, and then click Rename.
- Rename the file to use the original file name extension, such as .exe.
Change which file types are blocked
If you use a Microsoft Exchange Server account and the Exchange Server administrator has configured the Outlook security settings, the administrator might be able to help you. Ask the administrator to adjust the security settings on your mailbox to accept attachments such as the one that Outlook blocked.
If you do not use an Exchange Server account, there is an advanced procedure that you can use to unblock some file types. This procedure involves editing the registry in Windows. For more information about unblocking attachment file types, see the Microsoft Support article on blocked attachments in Outlook.
Attachment file types blocked in Outlook
| FILE NAME EXTENSION | FILE TYPE |
|---|---|
| .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 |
| .der | DER Encoded X509 Certificate File |
| .exe | Executable File |
| .fxp | FoxPro Compiled Source (Microsoft) |
| .gadget | Windows Vista gadget |
| .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, Internet 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) |
| .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 |
| .ops | Office Profile Settings File |
| .pcd | Visual Test (Microsoft) |
| .pif | Windows Program Information File (Microsoft) |
| .plg | Developer Studio Build Log |
| .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 |
| .ps1 | Windows PowerShell |
| .ps1xml | Windows PowerShell |
| .ps2 | Windows PowerShell |
| .ps2xml | Windows PowerShell |
| .psc1 | Windows PowerShell |
| .psc2 | Windows PowerShell |
| .tmp | Temporary File/Folder |
| .url | Internet Location |
| .vb | VBScript File or Any Visual Basic Source |
| .vbe | VBScript Encoded Script File |
| .vbs | VBScript Script File, Visual Basic for Applications Script |
| .vsmacros | Visual Studio .NET Binary-based Macro Project (Microsoft) |
| .vsw | Visio Workspace File (Microsoft) |
| .ws | Windows Script File |
| .wsc | Windows Script Component |
| .wsf | Windows Script File |
| .wsh | Windows Script Host Settings File |
| .xnk | Exchange Public Folder Shortcu |
