File Format & Compatibility

How to Convert Older Word Files to Microsoft 365 Format

Steve K Oct 12, 2026 868 views

Question details

The user wants to know if legacy Word documents (such as Word 2010 files) need to be converted to the modern Microsoft 365 format, and how to perform this conversion if necessary.

How to Convert Older Word Files to Microsoft 365 Format

Product: Microsoft Word
Device & OS: not provided
Scenario: Opening older .doc files in Microsoft 365, observing them open in Compatibility Mode, and deciding whether to update their file format.
Observed behavior: Older Word files open in Compatibility Mode, restricting access to newer Microsoft 365 features, or double-clicking the file opens an older version of Word instead of Microsoft 365.

Before you start

Before converting your older documents, verify if you need to share them with users on legacy systems or maintain exact original pagination, as updating the format might slightly alter the document layout.

Solution 1Recommended

Convert the Document Using the Info Menu

Use this built-in conversion tool to permanently update the current file from Compatibility Mode to the modern Microsoft 365 format.

This method updates the file in place. Once converted, you will be able to use all the latest Microsoft 365 editing tools and features that were previously locked.

Open the older document

Launch Microsoft Word and open the legacy document. You will likely see 'Compatibility Mode' in the title bar next to the document name.

Navigate to the Info tab

Click on the 'File' tab in the top-left corner of the ribbon, then select 'Info' from the left sidebar.

Convert the file

Click on the 'Convert' button located next to the Compatibility Mode section. A prompt will appear explaining that the document will be upgraded; click 'OK' to confirm.

Convert the Document Using the Info Menu

File Format Change: Converting the document this way replaces the old file with the new format. If you want to keep the original older version, use the Save As method instead.

Solution 2

Save a Copy as a Modern DOCX File

Use this method to create a modern version of the document while keeping the original older file intact as a backup.

Solution 3

Fix Default File Associations

If double-clicking an older file opens it in Word 2010 instead of your new Microsoft 365 application, update your system's default apps.

Convert Older Word Files Seamlessly with WPS Writer

WPS Writer offers native support for opening, editing, and converting legacy Word files. You can upgrade older documents to the modern format without worrying about layout distortion or compatibility issues.

1. Open your older file: Launch WPS Writer and open the legacy .doc file you wish to upgrade.
2. Access the Save As menu: Click the 'Menu' button in the top-left corner and select 'Save As' from the dropdown list.
3. Save as modern format: Select 'Microsoft Word Document (*.docx)' from the file type options, choose your save location, and click 'Save'.

100% compatible with legacy Microsoft Office .doc and modern .docx formatsLightweight application that opens older files rapidlySeamlessly converts documents while preserving your original formatting

microsoft office alternative - wps office

Frequently Asked Questions

Do I have to convert older Word documents to use them in Microsoft 365?

No, it is usually not required. Microsoft 365 can natively open and edit older .doc files. However, keeping them in the older format will lock them in Compatibility Mode, preventing you from using newer Word features.

What is Compatibility Mode in Word?

Compatibility Mode is a feature that temporarily disables new, advanced editing features in Word. This ensures that when you edit an older document, you don't introduce elements that would break the layout if the file is later opened by someone using an older version of Word.

Will converting my Word document ruin its formatting?

Generally, the formatting remains intact. However, because modern versions of Word use an updated layout and rendering engine, you might notice slight shifts in pagination or line breaks. Do not convert the file if maintaining the exact original pagination is critical.

Why does double-clicking a file still open Word 2010 after installing Microsoft 365?

This happens due to incorrect file associations in your operating system, where legacy .doc files are still linked to the older software. You can fix this by right-clicking the file, selecting 'Open with', choosing the Microsoft 365 version of Word, and setting it as the default application.

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