Q: Will an Import to my domain ever delete class content that teachers have created?
A: Imports will never delete classes teachers have created or delete the content within them.
If you are using Full Imports, and remove all or some of your classes from the classes.csv file in your import, or if you are using Partial Imports and add classes to a delete_classes.csv file:
For more details on how Imports are processed, check out the our specifications ( Full Import, Partial Import, Full Import version 2, or Partial Import version 2).
Planning on running a blank import file? See this article for information on what you can expect to see.