Is this happening frequently or there are times?
Try upgrading the Java and uninstall the spark client, delete everything in the installed folder.
Reboot system after upgrading Java
Install spark again
Does he/she has whiteboard or any other unofficial plugin (File > Plugins)? Also check the logs C:\Users\User\AppData\Roaming\Spark\logs
And if you want to start fresh, then rename whole Spark folder, not just the transcripts. You can then copy the transcripts from the renamed folder to the new one. Maybe also spark.properties file with settings.