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I get this error one one of my sheets. What does it mean? I cannot send email reports from that sheet anymore.

I was trying to email the reports to students this morning, it stuck on the screen " Preparing to generate reports.. " then nothing... what's going on?

Hi there, This has happened to me twice. I opened my gradebook and categories such as "weight" and "total marks" have suddenly disappeared from my assignments, and as a result when I try to import grades from Classroom, I get this error message: Error: Import unsuccessful: Exception: The number of columns in the data does not match the number of columns in the range. The data has 313 but the range has 312. Do I need an update? I can't afford to keep losing my grades!