When the game crashes, an autosave of the world will be created so you don't lose progress
follow this tutorial to set up mods on your plasma game and install this mod
After you get a Guru Meditation error, if the mod is enabled it will try to set all the devices in the world to be wireframe and save a copy of the world
When reentering the game after a Guru Meditation error, there will be a world in the world list that will probably have a white thumbnail and will show up first in the list. This is your recovered copy of the world.
Depending on the cause of your Guru Meditation error, the error might reoccur when you load back into the world. If this happens, not all is lost, you still have the data for the world, it's just the contents cause an error. If you contact hippolippo#2585 on discord, I can help you try to recover the save file so you don't lose you work