Microsoft Word Compare Documents Not Responding? Fixes

If Microsoft Word’s Compare Documents command is not responding, first give it a little time, then try comparing editable copies saved locally in the desktop app. Large or complex files, add-ins, protected documents, and sync or network delays can all make a comparison appear frozen; the steps below help identify the cause without risking your originals.

What Word’s Compare command does

Compare is designed to show differences between two versions of a Word document. In Word for Microsoft 365 on Windows, open the Review tab, select Compare, then choose Compare…. In the dialog, select the earlier file as the Original document and the later file as the Revised document. You can choose where Word displays the results; the usual choice is a new document.

The comparison result presents detected differences as revisions that you can review, accept, or reject. It does not overwrite either source file when you choose to create a new comparison document. Still, make backup copies before troubleshooting, especially if either source contains important edits that have not been saved.

A comparison may take longer than expected when Word must process many pages, images, tables, tracked changes, or complicated formatting. A temporary “Not Responding” message does not always mean Word has crashed. Repeatedly clicking Compare or launching several comparisons can add work while Word is still processing, so avoid doing that until you know whether the first attempt has finished.

Try these safe checks first

Wait briefly. If the documents are large, give Word a few minutes to finish. Avoid closing the app while it is working if you have unsaved changes. Check whether the window becomes responsive again.
Save copies of both files. Use File > Save As to create working copies, and keep the originals unchanged. If a file is in OneDrive, SharePoint, a shared folder, or a network location, save a copy to a local folder such as Documents and compare those local copies.
Close extra documents and apps. Close other Word windows and unnecessary programs, then retry. This can free memory and make it easier to tell whether the issue is specific to Compare or to Word generally.
Check that the files can be edited. Open each copy separately. If Word displays Protected View, only select Enable Editing when you trust the file and its source. Check for read-only status or editing restrictions; do not remove protection from a document unless you are authorized to do so.
Try a small test. Compare two short copies of a simple document. If that succeeds, the feature is probably working and the problem may be related to the original files’ size, structure, or storage location.

On Windows, if Word has stopped responding and does not recover, you can use Ctrl+Shift+Esc to open Task Manager. Ending Word can discard unsaved work, so use it only when waiting is no longer reasonable. On a Mac, Option+Command+Esc opens Force Quit; the same warning about unsaved changes applies. When Word restarts, check for a Document Recovery pane or recovered files before starting again.

Common reasons a comparison gets stuck

Large or intricate files: Many pages, embedded objects, high-resolution images, complex tables, or extensive tracked changes can increase the time required to compare.
Cloud or network access: A slow connection, pending sync, access permission, or a file that another person is editing can delay opening or saving. Local copies help distinguish a storage problem from a document problem.
File damage or unusual formatting: If one document has a problem, Word may struggle to open or process it. Test each file separately, and try a copy saved in the modern .docx format if you are working with an older .doc file.
Word add-ins: Some add-ins interact with documents or the ribbon and may interfere with an operation. A comparison that works when Word starts without add-ins is a useful clue.
Out-of-date or temporarily unstable Office: An update, restart, or Office repair may help if Word is freezing across multiple documents and tasks, not just one comparison.

These are possible causes, not a diagnosis: the same symptom can have different explanations. For example, a comparison that works locally but hangs on a shared file points toward access or sync conditions, while a failure limited to one document pair suggests investigating those files first.

Isolate a document or add-in problem

Open each source document by itself and check whether it loads, scrolls, and saves normally. If one file alone causes trouble, make another copy and test that copy. You can also create a new blank document, copy the text from the problem file into it, and save it as a .docx file. This may help when document structure is damaged, but copying content can leave out items such as headers, footers, comments, or specialized formatting. Keep the original as a reference and compare the new copy before relying on it.

On Windows, you can test Word in Safe Mode by closing Word, pressing Windows key+R, typing winword /safe, and pressing Enter. Safe Mode starts Word with certain customizations and add-ins disabled. If Compare works there, an add-in or customization may be involved. To review COM add-ins in normal Word, use File > Options > Add-ins. Beside Manage: COM Add-ins, select Go, then disable an add-in only if you recognize it and can safely test without it. Re-enable items one at a time to identify a possible conflict. Safe Mode steps differ on Mac; do not use the Windows command there.

Run Compare again with clear settings

Once Word is responsive, reopen the comparison dialog from Review > Compare > Compare… on Windows. Select the correct original and revised copies, and check that you have not accidentally selected the same file twice. Use the option to show changes in a new document if you want to preserve both inputs. The More >> control in the dialog exposes comparison options, such as whether to include formatting or comments. For an initial test, leave the default choices in place; if it succeeds, adjust options for the comparison you need.

If the dialog opens but Word appears to stall only after you select the files, try one file pair at a time, with other Word documents closed. Avoid changing the originals while the comparison is running. When the result appears, inspect it before accepting or rejecting revisions: differences in formatting, whitespace, or comments may be relevant even if the visible wording looks unchanged.

If Word continues to freeze across unrelated files, install available Office updates. On Windows, check File > Account > Update Options > Update Now when those controls are available for your installation. If the issue persists, Windows users can look for Microsoft 365 under Settings > Apps > Installed apps, choose its modification options, and run Quick Repair. Menu wording can vary by Windows and Office installation. Save work and close Office apps first.

Windows, Mac, and Word for the web

The steps above use the Microsoft 365 desktop app for Windows. Word for Mac also has a document comparison feature under the Review tab, though the precise labels and dialog layout can differ by version. If you do not see the same Windows controls, look for Compare on Review or check Word’s Help for your installed version. On Mac, Microsoft AutoUpdate or the Mac App Store may handle updates, depending on how Office was installed.

Word for the web has a different set of features and may not offer the same full comparison workflow as desktop Word. If Compare is missing or the browser version cannot complete the task, open the file in the Word desktop app and use its Review tools. Be careful with shared documents: opening a desktop copy and editing it separately can create a second version rather than updating the shared file.

Compare versus Combine

Compare is for finding differences between two versions, such as a draft and an edited copy. Combine is intended to bring revisions from multiple copies or reviewers together. These commands are related but are not interchangeable. If you are trying to see what changed between an original and a revised file, start with Compare. If several reviewers have each made tracked changes to separate copies and you need to bring their revisions together, investigate Combine instead. Review the resulting document carefully either way.

Frequently Asked Questions

Why does Word say Not Responding when I compare two documents?
Word may be processing a large or complex pair of files, waiting on a cloud or network location, or encountering a document or add-in issue. Wait briefly, then test local copies and a small document pair to narrow down the cause.

Can I close Word while Compare is running?
You can, but forcing Word to quit may lose unsaved changes or the comparison result. Wait first if possible. If you must force quit, reopen Word and check Document Recovery before repeating the comparison.

Will Compare change my original documents?
When you choose to display changes in a new document, Word creates a separate comparison result and leaves the two source files intact. Save backup copies anyway, and confirm the output location and settings in the comparison dialog.

Why is Compare greyed out in Word?
Check that you are using the desktop app and that a document is open. Also check whether the file is protected, opened in a restricted mode, or subject to editing restrictions. Interface availability can vary by Word version and context; do not remove security restrictions unless you have permission.

Does Word for the web compare documents?
The web app may not provide the full desktop comparison workflow. If Compare is unavailable or does not meet your needs, open the documents in the Word desktop app and use Review > Compare.

What should I do if only one pair of files causes the freeze?
Keep the originals, test each file separately, and compare local copies. If one document is the trigger, try a .docx working copy or copy its content into a new document, then check whether important elements were preserved before using the result.

When to use another approach

If Compare remains unreliable for one particular pair, a manual review may be more practical: open the files side by side and inspect the sections that changed. For a cloud-stored file, Word’s version history may help you locate an earlier version, but it serves a different purpose from comparing two separately edited documents. Avoid uploading confidential or sensitive documents to an online comparison service unless your organization permits it and you understand how the service handles the files.

For most users, the best next move is to protect the originals, move working copies to a local folder, and test Compare with other documents. That simple process separates a Word-wide problem from a file-specific or storage-related one, and keeps troubleshooting from putting the source documents at risk.

Try it: the Date Difference Calculator: days, months, years and weekdays between two dates, with the DATEDIF formulas.

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Sources: Function behaviour and menu paths: Microsoft Support documentation for Excel. Method & sources

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