Hello,

If you download Quiz statistics report as .xlxs-file when there is submissions in the quiz Excel says the file is corrupted.

Tried with local installation of Excel 2010 and online o365 Excel.

Tested with Moodle Moodle 3.5.13+ (Build: 20200729)

Steps to repeat:

1. Create a quiz
2. Create one true/false question (dog is an animal)
3. As a teacher/manager or administrator open quiz -> statistics
4. Under "Quiz information"-topic "Download full report as" and "Microsoft XLS(.xlxs)"
5. Press download
6. Open the file in Excel and notice how everything works
7. Answer as a student to the quiz
8. Repeat the process as teacher and notice how Excel claim that file is corrupt.