Sorry about the problem. I think there should be some backup files created in background. Please look into your workspace folder where your .vpp project file is stored in. See if you can find any file named like my_project.vpp.bak_000f. Those are the backup files. Please shutdown Visual Paradigm. Then, rename the existing .vpp file to something else. After that, remove the .bak_000f part of the latest backup file, and try to open it in Visual Paradigm. Hopefully, your work can then be restored.
About the problem, could you check the bin folder under the Visual Paradigm installation directory, see if there are any .log files. If yes, could you zip and upload the file here? Meanwhile, we will study your case in detail and conduct some testing based around your report. Again, sorry for the inconveniences caused.