Assuming you are still on SVN. Try to fix the confict via Tortoise svn. This is an external tool that can help you solve conflict outside Mendix Studio Pro.
Hi Khaled,
You can use TortoiseSVN to resolve file conflicts as described here: https://docs.mendix.com/refguide/using-version-control-in-studio-pro#9-working-outside-studio-pro
Maybe try to make a snapshot this way in both branches first?