Excel - Issues and Problems

Windows - General

Issue: Unable to read file error message when you open Excel file.
Solution: You will need to turn off "Auto-recovery". Full instructions can be found here.

Issue: I am unable to open a file by just double-clicking on the file. But I can open the file if I go into Excel first.
Solution: You will need to turn off "Ignore other applications". This can be found in Tools > Options > General.