Document Editing Problems

How to Fix Cannot Merge PDF Documents in OneDrive or Microsoft 365

WPS Editor Sep 29, 2026 870 views

Question details

Users are unable to proceed with merging documents in OneDrive or Microsoft 365 because the interface button is unresponsive.

How to Fix Cannot Merge PDF Documents in OneDrive or Microsoft 365

Product: OneDrive and Microsoft 365
Device & OS: not provided
Scenario: Attempting to merge two or more PDF documents using the online Microsoft 365 document processing tools.
Observed behavior: The Next button remains inactive and grayed out, preventing the user from completing the document merge process.

Before you start

Ensure you have a stable internet connection and that the files you are trying to merge have completely finished uploading to your OneDrive account without any sync errors.

Solution 1Recommended

Verify File Formats and Edit Permissions

Ensure the selected files are supported PDFs and that you have the necessary edit permissions to process them in Microsoft 365.

The document merge feature in Microsoft 365 specifically supports standard PDF files. Selecting incompatible formats, encrypted PDFs, or files you only have view access to will prevent the Next button from activating.

Check file extensions

Navigate to the files in OneDrive, right-click, and select 'Details' to confirm they are standard .pdf extensions rather than Word or image files.

Verify permissions

In the file details pane, ensure you are listed as an owner or have full edit permissions for the documents. View-only access restricts merging.

Remove password protection

If the PDFs are encrypted or password-protected, open them in a desktop PDF editor, remove the security restrictions, and re-upload them to OneDrive.

Select valid files

Click the checkmark next to exactly two or more supported PDF files. The Next button should now become active.

Verify File Formats and Edit Permissions

Microsoft Documentation: Always refer to Microsoft's official document processing guidelines to ensure your files meet the size and page limits for online PDF merging.

Solution 2

Refresh Browser Session and Clear Cache

Resolve browser-related caching glitches or session timeouts that cause UI elements like the Next button to freeze.

Seamless PDF Merging

Merge PDF Documents Instantly with WPS Office

Skip the online browser glitches and OneDrive sync issues. WPS Office provides a powerful, built-in PDF toolkit that allows you to effortlessly combine multiple PDF files into one directly on your local device.

1. Open WPS Office PDF Toolkit: Launch the WPS Office desktop application and click on the 'PDF' tab on the home screen.
2. Select Merge PDF: Locate and click on the 'Merge PDF' tool within the PDF features menu.
3. Add your files: Click 'Add Files' and select the PDF documents you want to combine from your local computer drive.
4. Merge documents: Arrange the files in your preferred reading order and click the 'Merge' button to instantly combine them into a single PDF file.

Merge unlimited PDF documents offline with just a few clicks.Fully compatible with all standard PDF files created in Microsoft 365, Word, and other tools.Eliminates the frustration of browser session timeouts or inactive UI buttons.Comprehensive PDF editing, splitting, converting, and compressing features included.

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Frequently Asked Questions

Why is the Next button grayed out when merging files in OneDrive?

The Next button typically remains grayed out or inactive if you have selected incompatible file types (such as Word documents instead of PDFs), if the PDFs are password-protected, or if you lack edit permissions for the selected files.

Can I merge Word documents directly in OneDrive?

No, Microsoft 365's online document merging feature is primarily designed for PDF files. To combine Word documents, you must open them in a desktop word processor and use the 'Insert Object from File' feature.

Does password protection prevent PDF merging in Microsoft 365?

Yes. If one or more of the PDF files you are attempting to merge are password-protected or restricted from editing, the online system will not be able to process them, causing the merge function to stay disabled.

Document & File Issues