When you double-click a Word document, you might see an error message that says Word cannot open this file because it is blocked by your file block settings. This happens because Word’s Trust Center has a security feature that prevents opening certain older or potentially unsafe file formats. The setting is enabled by default for file types like Word 2003 binary documents, templates, and add-ins. This article explains how to locate and modify the file block settings in Word so you can open those specific files safely.
Key Takeaways: Changing File Block Settings in Word
- File > Options > Trust Center > Trust Center Settings > File Block Settings: Lists every file type Word can block and lets you enable or disable each block.
- Open behavior options: For each blocked type, you can set Word to not open the file, open it in Protected View, or allow opening normally.
- Registry key for IT administrators: The setting can also be deployed via Group Policy using the registry path HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\16.0\Word\Security\FileBlock.
Why Word Blocks Certain File Types
Word uses file block settings to protect your computer from files that might contain malicious code. Older binary formats, such as .doc from Word 97-2003, .dot templates, and .wll add-ins, do not have the same security protections as the modern Open XML formats (.docx, .dotx). Microsoft introduced file block settings in Word 2010 and has kept them in every version since, including Word for Microsoft 365, Word 2021, Word 2019, and Word 2016.
When a file type is blocked, Word displays a warning and refuses to open the file normally. You can override this behavior by either disabling the block entirely or setting the file to open in Protected View. Protected View opens the file in a sandboxed environment where editing is disabled until you click Enable Editing.
Steps to Modify File Block Settings in Word
Follow these steps to change which file types Word blocks and how it handles them.
- Open the Trust Center
In Word, click File in the top-left corner. Then click Options at the bottom of the left pane. In the Word Options dialog, click Trust Center in the left pane, then click the Trust Center Settings button. - Locate File Block Settings
In the Trust Center dialog, click File Block Settings in the left pane. A list of file types appears. Each file type has a checkbox and a dropdown menu for open behavior. - Unblock a specific file type
Find the file type you need to open, such as Word 97-2003 documents and templates. Clear the checkbox next to that file type to completely remove the block. Alternatively, keep the checkbox checked and change the open behavior dropdown to Open in Protected View or Open in Protected View and allow editing. The last option lets you edit the file after clicking Enable Editing. - Apply the change
Click OK in the Trust Center dialog, then click OK in the Word Options dialog. Close Word and reopen it. The blocked file type should now open without the error.
Method 2: Change File Block Settings via Registry for Multiple Users
If you manage multiple computers in a business environment, you can configure file block settings using the Windows Registry or Group Policy. This method is faster than changing settings on each machine.
- Open Registry Editor
Press Windows + R, type regedit, and press Enter. If prompted by User Account Control, click Yes. - Navigate to the Word File Block key
Go toHKEY_CURRENT_USER\Software\Policies\Microsoft\Office\16.0\Word\Security\FileBlock. If the key does not exist, right-click the Security folder, select New > Key, and name it FileBlock. - Add a DWORD for the file type
Right-click the FileBlock key, select New > DWORD (32-bit) Value. Name it after the file type you want to unblock. For example, for Word 97-2003 documents, name it OpenInProtectedView. Set the value data to 0 to disable the block, 1 to open in Protected View, or 2 to open in Protected View with editing allowed. - Apply and test
Close Registry Editor. Restart Word and test opening the previously blocked file type.
What to Do If Word Still Blocks the File After Changing Settings
File Block Settings Keep Resetting After Restart
If the file block settings revert after you close Word, a Group Policy applied by your IT department is likely overriding your changes. Contact your system administrator to adjust the policy. You can check this by opening a command prompt as administrator and running gpresult /h gpresult.html, then opening the generated HTML file to see which policies are applied.
Word Displays a Different Error About File Corruption
If after unblocking the file type Word shows a message that the file is corrupt, the document itself is damaged. Try using the built-in Open and Repair feature: click File > Open, select the file, click the arrow next to the Open button, and choose Open and Repair.
File Block Error Only Appears for One Specific Document
If only one document triggers the block, the file might have been saved with a mismatched extension. For example, a .docx file that is actually a .doc file inside. Rename the file to the correct extension or use Open and Repair to attempt recovery.
File Block Settings Comparison: Default vs Custom Configuration
| Item | Default Setting | Custom Setting |
|---|---|---|
| Word 97-2003 documents (.doc) | Blocked (Open in Protected View) | Not blocked or Open in Protected View with editing |
| Word 2003 templates (.dot) | Blocked (Open in Protected View) | Not blocked or Open in Protected View with editing |
| Word 2003 add-ins (.wll) | Blocked (Do not open) | Open in Protected View or allow editing |
| Word binary documents (.doc) from unknown source | Blocked (Open in Protected View) | Not blocked or Open in Protected View with editing |
| Word 2000-2003 binary documents and templates | Blocked (Open in Protected View) | Not blocked or Open in Protected View with editing |
You can now open files that were previously blocked by Word’s file block settings. After changing the setting, test with a file of the same type to confirm the error no longer appears. For ongoing security, consider leaving the block enabled but setting the behavior to Open in Protected View instead of completely disabling the block.