Really need help with this Excel is this a glitch or what?

Ok... so i have asked this question before and no one can give me an answer. I am in the military and i consolidate reports to send to higher up. We receive reports from our lower and what I have donw is come up with an excel spreadsheet that calculates numbers to give totals. So when we receive the reports from our subordinates i click copy and paste from there excel sheet into the main excel sheet. This was never an issue until recently when i paste it in the main sheet everything goes blank. Nothing shows. I try to use older reports and change the numbers to reflect the recent and eventually it will start with the same problem. What will sometimes also happen is everything looks fine, i save and when I open it up the next day and error shows "Excel found unreadable content in 'File Name.xlsx'. Do you want to recover the contents of this workbook? If you trust the source of this workbook, click Yes." and this happens usually after I get blank pastes. Somone please help