How do I compare two versions of a document without overwriting either one?
Quick answer
Keep the original and revised documents as separate files, then set the comparison result to a new document or copy—not either source. In desktop Word for Windows, Legal Blackline displays differences in a new third document by default; choosing either source as the results location modifies it. Word 2019 for Mac displays differences in a new copy based on the original. [S1] [S2]
The question, the details, the next step.
I have an older document and an edited version. I want to see what changed, but I don’t want the comparison to replace either file. What should I do?
Keep the two versions as separate files and direct the comparison result to a third document rather than either source. That lets you review the differences while retaining the original and revised files.
In desktop Word for Windows, Legal Blackline compares an original and a revised document and, by default, displays the differences in a new third document. You can choose comparison options such as text changes, formatting, and comments. Avoid choosing either source document as the results location: that modifies the selected document. [S1]
Before you begin, give the files distinct names, such as [Project]_original.docx and [Project]_revised.docx. These are examples, not required naming rules.
How do I avoid selecting the wrong file or comparing details I don’t need?
Identify which file is the original and which is the revision before opening the comparison tool. Check the file names or other information available in your file manager rather than relying on memory. Then select the files in the appropriate roles and review the comparison options before starting.
For example, if your review is about wording, decide whether formatting and comments are also relevant. Desktop Word for Windows provides options for comments, formatting, and text changes, so choose what fits your review. [S1] The comparison shows differences; you decide which changes, if any, to accept.
What should I check when the comparison is finished, and what if I use Word on a Mac?
Check that the result is a new document or copy, and that it shows differences between the intended pair of files. Save it with a distinct name, such as [Project]_comparison_[date].docx, and keep the two source files separate.
For Word 2019 for Mac, Microsoft describes comparison results with revision marks in a new copy based on the original, leaving the original copy untouched. Those instructions apply specifically to Word 2019 for Mac; don’t assume every Word version or other editor has the same menus or behavior. Check your version’s comparison options and choose a separate output if offered. [S2]
Can you give me a short workflow I can reuse for each review?
Use this sequence:
- Identify the original and revised files, and give them distinct names.
- Open the comparison feature and select the two files in the correct roles.
- Choose relevant comparison details, such as formatting or comments, if those options are available.
- Set the result to a new document or copy—not either source file.
- Review the result and save it under a separate name, keeping both source files unchanged.
For example, your files might be [Project]_original.docx, [Project]_revised.docx, and [Project]_comparison_[date].docx. Check the result destination before starting: the cited Word instructions cover specific versions and do not establish how every app or edition behaves. [S1] [S2]
A practical checklist
Identify which file is the original and which is the revised version.
Give the two source files distinct names.
Select only the comparison options relevant to the review.
Choose a new document or copy for the result, not either source.
Check that the result compares the intended files and save it under a separate name.
A few more useful answers
Does the comparison decide which edits I should keep?
No. It helps you inspect differences; you decide which changes to accept or apply.
Do the same menu steps apply to every document editor?
No. The cited instructions cover specific Word versions, not every editor or edition. Check your app’s options and choose a separate results file where available.
Can I include formatting and comments in the comparison?
Desktop Word for Windows offers options including comments, formatting, and text changes. Choose what suits your review, and check your version’s available options. [S1]
Sources
References used for this guide.
- [S1] Compare document differences using the legal blackline option support.microsoft.com · Checked
- [S2] Compare and merge two versions of a document support.microsoft.com · Checked