Is this issue occurring for a specific project, or all projects you try to open?
If it's a specific project, please submit a bug report here with a copy of the project file that causes the crash, as well as your Twinmotion log files (Where to find Twinmotion .log file) from when you crashed.
If it's for any project you try to open, please submit the bug report with your log files and try following the steps in the Twinmotion is not visible after splash screen article to reset Twinmotion to a default configuration, which can sometimes help resolve issues that occur during startup/loading.