Office Compatibility Issues

Why is the Similarity Checker Missing in Office LTSC Professional Plus 2021?

Olivia Miller Oct 10, 2026 869 views

Question details

The user is trying to find or enable the Microsoft Editor and similarity checker tools in their version of Office, but the features are unavailable.

Why is the Similarity Checker Missing in Office LTSC Professional Plus 2021?

Product: Office LTSC Professional Plus 2021
Device & OS: not provided
Scenario: Attempting to check document similarity or use advanced Microsoft Editor features in Word.
Observed behavior: The Editor button and similarity checker are missing from the ribbon, and attempting to add them manually to the ribbon fails to restore functionality.

Before you start

Verify your exact Microsoft Office version by opening a Word document, clicking on 'File' in the top-left corner, and selecting 'Account' to confirm whether you are using a perpetual license or a Microsoft 365 subscription.

Solution 1Recommended

Understand Microsoft Office Perpetual License Limitations

Clarify why cloud-based features like the Similarity Checker are excluded from Office 2021 perpetual licenses.

Office LTSC Professional Plus 2021 is a perpetual (one-time purchase) version of Microsoft Office. Unlike Microsoft 365, which is subscription-based and continuously updated with cloud-powered features, perpetual versions have a locked feature set.

Because the full Microsoft Editor experience—including the similarity checker—relies heavily on Microsoft's cloud computing and premium servers, it is strictly exclusive to Microsoft 365 subscribers.

Check your license information

Open Microsoft Word, click on the 'File' menu, and select 'Account'. Look under the 'Product Information' section to see your exact Office edition.

Use basic spelling and grammar tools

Navigate to the 'Review' tab on your ribbon and click 'Spelling & Grammar'. While the advanced similarity checker is missing, standard proofreading tools are still functional.

Upgrade to Microsoft 365 (Optional)

If you absolutely require the Similarity Checker for your workflow, visit the Microsoft website to purchase and switch to a Microsoft 365 subscription plan.

Understand Microsoft Office Perpetual License Limitations

Customizing the Ribbon: Even if you right-click the ribbon, select 'Customize the Ribbon', and manually add the 'Editor' button, the feature will remain disabled or hidden because the software license does not support it.

Free Microsoft Office alternative

Try WPS Office for a Feature-Rich Document Editing Experience

If your current perpetual version of Microsoft Office is limiting your access to essential editing features, consider switching to WPS Office. It provides a lightweight, highly compatible, and free alternative with comprehensive built-in document reviewing capabilities.

1. Download the software: Visit the official WPS website and click the 'Download WPS Office Free' button to get the installer.
2. Install WPS Office: Run the downloaded setup file and follow the simple on-screen instructions to install the suite on your computer.
3. Open and edit your files: Launch WPS Writer, navigate to 'Menu' > 'Open', and select your existing .docx files to start reviewing and editing your documents immediately.

Completely free to download and use with a highly intuitive, familiar interface.Fully compatible with Microsoft Word formats (.docx, .doc), ensuring seamless document migration without data loss.Includes comprehensive spell check, word count, and document review features out of the box to enhance writing quality.Lightweight installation that runs smoothly on almost any device without requiring an expensive cloud subscription.

microsoft office alternative - wps office

Frequently Asked Questions

Can I manually add the Microsoft Editor to the ribbon in Office 2021?

No. While you might find the Editor command in the 'Customize Ribbon' settings, adding it to your ribbon will not work. The button will remain grayed out or hidden because the underlying cloud feature is not licensed for Office 2021 perpetual versions.

Is there a free way to access the Microsoft Editor Similarity Checker?

You can access basic Microsoft Editor features by using the free web version of Microsoft Word (Word for the Web) with a free Microsoft account. However, premium features like the Similarity Checker may still require a Microsoft 365 subscription.

Will updating Office LTSC Professional Plus 2021 eventually add the Similarity Checker?

No. Office LTSC Professional Plus 2021 receives regular security and stability updates, but it does not receive new feature updates. The feature set was permanently locked at the time of its release.

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