Four lessons to be learnt from your current problem.
1. Always make a backup copy of your current version before you upgrade to a newer version. In your case you could have just deleted the whole directory, if installed correctly, and then copied back the previous version to the correct directory structure
2. Attach your current log.txt file which is created immediately after a crash or you shut down. In doing so others who have a greater knowledge base regarding X-Plane could try and ascertain what the problem may be.
3. The current stable Laminar Research version of X-Plane, provided yours is not the steam version, is 11.11 and has been for some time while 11.20 beta versions are still being sorted out. Try the upgrade. This version will not mix with the Steam version should you have steam. Steam is always slower in the upgrade versions.
4. Run the installer file and it will check on damaged files and restore them giving a stable overall version.
Glenn