**Source URL:** https://regulatoryone.veevavault.help/en/lr/1804/index.md

# Comparing Document Versions

During a document's complete lifecycle, it may undergo many changes. Vault allows you to compare two versions of a document to see what has changed between them. Note that you must have _View Content_ and _View Document_ permission on both versions.

For documents with more than one version, click **Compare Versions** (<img class="inline" src="https://platform.veevavault.help/assets/images/platform_document_viewer_compare_versions.png" alt="Compare Version button" style=" width: auto;" />) on the document viewer toolbar. Vault opens the document in comparison mode and compares the currently viewed version with the most recent previous major version to which the user has access. The _Compare Versions_ button is not displayed on the document viewer toolbar when there is no previous major version or the user does not have access to a previous major version.

You can also compare versions from the [**Version History** dialog](/en/lr/162/) or the _Version History_ section of the _Information_ panel on the Doc Info pane.

## Comparison Mode

When you compare two versions, Vault opens the document in comparison mode. In this mode, inserted text is highlighted in purple and deleted text is marked with a note. A banner is displayed above the document viewer with information about which versions you are comparing.

You can close comparison mode using the **Back to previous page** link.


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      <p><strong>Note</strong>: For customers who have licensed Vault AI, comparison mode displays a <a href="/en/lr/950642/#document-comparison">comparison summary</a> in the Vault AI Chat window in Panel View.</p>
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## Comparing Two Different Documents

If you want to compare two different documents instead of two versions of the same document, you can open both documents in [_Split Screen_ mode](/en/lr/9753/#split-screen-mode) and manually review them. _Compare Versions_ cannot compare two different documents to each other using comparison mode.

## Limitations

There are some limitations to document comparison:

* Vault detects changes to text only. Vault does not detect changes to images, tables, formatting, page additions or removals, or other structural changes.
* Vault cannot detect changes in text that is not searchable, for example, text in image files.
* When large portions of a document change, or when a document changes structurally, the number of changes may be so large as to make document comparison unhelpful.
* When Vault detects more than 5,000 distinct changes between versions, it does not display any changes.
* Vault does not add a note for text deleted from the end of a document. To see content removed from the end of a document, you must compare a previous version that has the removed text to a newer version that does not have the text. The missing text is considered an addition and is highlighted purple.
* In rare cases, Vault detects extra spaces that do not exist. This causes unchanged text to be highlighted as changed.
* Vault may be unable to correctly identify changes between versions when the file formats vary, such as comparing a .DOC file to a .DOCX file or comparing a .CSV file to an .XLSX file.