After engine version update, all project files crash without exception

Development Programming & Scripting Blueprint
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Hello, to better give input to your question

  1. Make a backup of the original project before upgrading
  2. From what version did you upgrade, and to which version?
  3. Do you have any additional plug-in’s, if so did you upgrade these plug-in’s too?
  4. Assuming you do not have a C++ project, delete the following folders: DerivedDataCache, Intermediate, Saved.
  5. If you have additional plug-in’s, disable them or move the plug-in folder out of your project. NOTICE, that once you can open the project do not save content, it will break plug-in related code.
  6. Upgrade plug-in’s and enable them once by one to check which may or may not cause issues.