Storm season is back, bringing with it the potential for significant weather events. If you have clients in areas prone to infrastructure disruption, visit the Disaster Recovery Resources guide for preparedness information. Datto recommends performing proactive disaster recovery testing to mitigate potential downtime. See our articles about the importance of disaster recovery testing and Preparing For A Cloud Virtualization Test: Policies, Procedures, And Partner Responsibilities to learn more. For live updates, follow @datto on Twitter.

How Do I Use WinMerge to Investigate Large Backups?



This guide explains using WinMerge to investigate changes within backups.


  • Datto SIRIS
  • Datto ALTO
  • Datto NAS
  • WinMerge (Installed or Portable)
  • Microsoft Visual C++ 2008 Runtime Components
  • Microsoft Windows XP/2003/Vista/2008/7/8/2012


WinMerge is a free, third-party tool that you can use to identify growth and change between backup snapshots. The application presents differences in a text format that is easy to understand.


1. Download WinMerge from the developer websiteDatto does not recommend downloading applications from any third-party websites.

Figure 1: Download and install WinMerge

2. Install the application on a server or workstation on the same LAN as the Datto appliance by using the appropriate installer. Be sure to read all prompts during the installation process, and only allow WinMerge to install. If installing the portable version, ensure that Microsoft Visual C++ 2008 Runtime Components are installed prior to using.

3. Log into the Datto appliance's web UI and mount two file restores. One restore should be from the date when the large backup happened, the other should be from the time and date just before the size of the backup increased.

4. Launch WinMerge and go to Edit > Options... > Compare > Folder and change the compare method dropdown to Modified Date and Size.

Figure 2: Change the Compare method

5. In the Restore tab of the Web UI, obtain the the network paths for both file restores.

6. In WinMerge, go to File > Open... In the Left field, enter the network path of the older file restore. In the Right field, enter the network path of the more recent file restore. Leave the Filter field as *.* to compare all file extensions. Check the Include Subfolders box.

Figure 3: Enter the file paths

7. Once the above fields are populated, choose OK. The Comparison result, Left Date, and Right Date columns will show modifications to files.

img4.pngFigure 4: View comparisons

Additional Resources



Was this article helpful?

1 out of 1 found this helpful

You must sign in before voting on this article.

Calling all Partners! We want to hear your feedback! Please participate in this quick survey and help us build a better, more-relevant Knowledge Base!

Want to talk about it? Head on over to our Community Forum!