MarginDiff Documents compares text and supported formatting, comments, fields, images
and document structure. It is suited to reviewing versions of contracts, reports,
policies and other text documents.
## Start a comparison
1. Open MarginDiff Documents and start a new comparison.
2. Select the earlier document in **Original**.
3. Select the revised document in **Modified**.
4. Choose the comparison or style profile appropriate to your review.
5. For PDF inputs, enable **OCR** after checking the
[OCR requirements](/docs/documents/pdf-ocr).
6. Select **Start** and wait for conversion and comparison to finish.
Use **File > Stop** to cancel a running comparison. Stop is enabled from the start
of preparation through text comparison, including a comparison started with
**Switch**. Microsoft Word conversion runs in the background and can be stopped
while waiting for Word. Native editor operations may need to finish their
current step. An unfinished new comparison closes; a stopped Switch clears its
unfinished redline.
If the files are reversed, use **Switch (F4)**. Check the
[comparison direction](/docs/getting-started/#choose-the-comparison-direction).
The menu beside each input can open its location in Explorer or the document in
Word or a PDF viewer. Use it to inspect an input before starting.
## Choose the scope of the review
[Comparison options and profiles](/docs/documents/options) explains wording,
formatting and table settings, including reusable profiles and session overrides.
## What happens next
Continue with [Review differences](/docs/documents/review) to navigate the result,
then [Save and export](/docs/documents/save-export).
If conversion or loading fails, resolve the reported problem before treating the
comparison as complete. See [Troubleshooting](/docs/troubleshooting).