How to Fix Copilot Error ‘We Couldn’t Open This File’ in Word

When you use Copilot in Microsoft Word, you may see the error message “We Couldn’t Open This File.” This error stops Copilot from analyzing your document or generating content based on it. The issue typically occurs because Copilot cannot access the file due to file format restrictions, permission blocks, or a corrupted file cache. This article explains the exact causes and provides step-by-step fixes to resolve the error quickly.

Why Copilot Shows “We Couldn’t Open This File”

Copilot in Word relies on direct access to the file’s content to generate summaries, rewrite text, or answer questions about the document. The error occurs when Copilot’s file handler cannot read the file stream. This can happen for three main reasons.

File Format Is Not Supported

Copilot only supports the Open XML format .docx. Older formats such as .doc from Word 97-2003, .rtf, .odt, and .txt are not readable by the Copilot engine. If you open such a file, Copilot will not be able to parse its internal structure and will return the error.

File Is Stored in a Blocked Location

Word applies Protected View to files downloaded from the internet or received as email attachments. Files in Protected View are sandboxed and read-only. Copilot cannot access the content of a Protected View document. Similarly, files stored on certain network shares or SharePoint sites with restricted permissions may be unreachable.

Local File Cache Is Corrupted

Word maintains a local cache of recently opened files. When this cache becomes corrupted, the file handler fails to load the document for Copilot. This is the most common cause after a Microsoft 365 update or a forced shutdown.

Steps to Resolve the Copilot File Open Error

Follow these steps in order. Test Copilot after each step by opening a new or existing .docx file and typing a request in the Copilot pane.

Step 1: Convert the File to .docx Format

1. Open the file in Word
   If the file is in .doc, .rtf, or .odt format, open it normally. Word will show a yellow bar indicating compatibility mode.
2. Go to File > Save As
   Choose a location such as This PC or OneDrive.
3. Select Word Document .docx from the Save as type dropdown
   Do not choose Word 97-2003 Document .doc or any other format.
4. Click Save and close the file
   Reopen the new .docx file. Copilot should now be able to read the content.

Step 2: Disable Protected View for the Current File

1. Check the yellow Protected View bar at the top of the document
   If the bar says “Protected View” and “This file originated from an Internet location,” the file is sandboxed.
2. Click the Enable Editing button on the yellow bar
   Word will exit Protected View and allow full editing access.
3. Open the Copilot pane
   Click the Copilot icon on the Home tab or press Alt+I. Try your request again.

Step 3: Clear the Word File Cache

1. Close Word completely
   Make sure no Word process is running in the background. Check Task Manager if needed.
2. Press Win+R to open the Run dialog
   Type %localappdata%\Microsoft\Office\16.0\OfficeFileCache and press Enter.
3. Delete all files inside the OfficeFileCache folder
   Select all files with Ctrl+A and press Delete. Empty the Recycle Bin.
4. Restart Word and open the document
   Word will rebuild the cache. Copilot should now be able to access the file.

Step 4: Grant File System Permission to Word

1. Open Windows Settings
   Press Win+I and go to Privacy & security > File system.
2. Ensure “Let apps access your file system” is turned On
   If it is Off, toggle it to On.
3. Scroll down to “Choose which apps can access your file system”
   Find Microsoft Word in the list and make sure its toggle is set to On.
4. Restart Word
   Open the file and test Copilot again.

Step 5: Repair Microsoft 365 Installation

1. Open Control Panel
   Press Win+R, type appwiz.cpl, and press Enter.
2. Find Microsoft 365 in the list
   Right-click it and select Change.
3. Select Quick Repair and click Repair
   Follow the on-screen prompts. This will fix corrupted installation files without removing your data.
4. Restart your computer
   Open Word and test Copilot. If the error persists, run an Online Repair from the same dialog.

If Copilot Still Has Issues After the Main Fix

Some scenarios require additional steps beyond the standard fixes. Use the following troubleshooting approaches based on your situation.

Copilot Error Occurs Only on OneDrive or SharePoint Files

If the file is stored on OneDrive or SharePoint, check the sync status. Open File Explorer, right-click the file, and select “Always keep on this device.” Wait for the file to download fully. Then open it from the local folder, not the web browser. Also verify that your Microsoft 365 license includes Copilot. Go to File > Account and confirm that Copilot appears under Subscriptions.

Copilot Error Occurs After a Microsoft 365 Update

A recent update may have changed the default file handler. Open Word, go to File > Options > Trust Center > Trust Center Settings > Protected View. Uncheck all three options under Protected View. Click OK and restart Word. This allows Copilot to access all files without sandboxing. Re-enable these options after testing to maintain security.

Copilot Error Occurs with Large or Complex Files

Files exceeding 10 MB or containing many embedded objects can trigger the error. Save a copy of the document, remove large images or embedded tables, and test Copilot on the simplified version. If Copilot works, the original file had structural issues. Use the Document Inspector under File > Info > Check for Issues to remove hidden data that may interfere.

Copilot File Access Error vs Other Copilot Errors: Key Differences

Item	“We Couldn’t Open This File”	“Copilot Is Not Available”
Root cause	File format, cache, or permission issue	Missing license, service outage, or disabled feature
Primary fix	Convert to .docx and clear cache	Check Microsoft 365 subscription and restart Word
When it appears	Immediately after opening a file and opening Copilot	When clicking the Copilot icon in the ribbon
Scope	Affects only the current document	Affects all documents in the session

The “We Couldn’t Open This File” error is file-specific. The “Copilot Is Not Available” error is account-specific. Use the table above to determine which set of fixes applies to your situation.

After applying the steps in this article, you should be able to use Copilot in Word without the file access error. Start by converting any non-.docx files and clearing the Office file cache. If the error persists on a specific file, use Document Inspector to remove hidden content. For recurring issues, run the Microsoft 365 Quick Repair tool from Control Panel.