I have a problem and sure that it started after a windows 10 update. My FE DB give error 94 (invalid use of null). This happened when I want to add a new record.
See the response by Minty "Invalid Use of Null" in the Similar Threads at bottom of the page. MsgBox and error handler will identify the issue. No need to deal with or have an ACCDE. Ignore the ACCDE.