How to prevent changing of Author in Microsoft Excel

I am teaching my class excel and the students have to save their homework files to a network folder designated for them. I recently caught students taking copies of their homework files and transferring them via thumb drives to other students folders. the only reason I knew they did this was because I looked at the author property in file-properties and saw that the original author was not the user in whose folder it was in. I have a feeling as soon as i confront the students about cheating they will be looking for how I found out and a way around this. You can easily change the author on a file and I was wondering if anyone knew of a way to prevent this. Is there a registry entry that can be edited so that the author box is filled in automatically with the original user but can't be edited. Any help would be very appreciated.

So you'd add this registry entry to their home PCs how?<g> No, no such entry in any case. I'm afraid that file properties are readily editable. It's probably impossible to know for certain who first saved a file. If you gave each student a file to start with, and each was subtlety different that might be a trace. But that's a lot of trouble, not fail safe and doesn't prevent students from 'sharing' the work that goes into completing the spreadsheet if not the spreadsheets themselves.

For that you can block the excel sheet so that no one can modify the file summary. To avoid losing the contents of a cell or inadvertently change a value, you can lock access to the contents of a cell. Add this, select the cell in question, go to Format > Cells, click the Protection tab and check the Lock (normally it is checked by default). For a record to be kept out of any changes of cell contents or formatting, you must enable the protection of the sheet. Go to Tools> Protection> Protect Sheet. Enter a password to enable protection. You can still allow certain actions of the workbook by selecting from the list. Click on OK. All cells are marked as Locked readable but not editable.

In Excel, can be handy to convenient security feature of the worksheet in case we need to distribute it to other users to compile a number of fields. In the Protect Sheet mask you can also choose a list of options to be granted any permissions to the user. Following the return of completed sheets, we can remove the protection from the menu by selecting Tools > Protection voice Unprotect Sheet.