Are you using the latest beta 1.7 version? (it was last updated April 30th).
If there is a “LightBurn_Crash_Log.txt” file on your desktop, please send it to support@LightBurnSoftware.com and include a link to this forum post. If you cannot find the crash log, please turn on the debug mode (Help>Enable Debug Log) and go through the steps that cause the crash, then close LightBurn and look in your Documents folder for LightBurnLog.txt, and send it in to support.