One of the issues with SharePoint Designer 2013 based workflows registered by many users is the issue of not opening or loading the workflow while the workflows move from a site on one farm to another.
While working on moving a site to a new farm using the Database Backup/Restore procedure, it can be noticed that some SharePoint Designer 2013 workflows are fine while some others are completely blank, meaning they have no steps in them. Would the Database Backup/Restore be the right approach? How about SharePoint Site Backup/Restore or Export/Import?
When comparing SharePoint Designer 2013 versions it can be found that some are slightly different. The SharePoint Designer version that is more advanced does not have this issue. If you install SPD 2013 SP1, you can open the workflows successfully.