If an Excel File that should be accessible will not open because of "Restrictions", and individual permission rights did not alleviate the issue It may be an issue with Macros.


Microsoft is phasing out Macros in Excel as they are an easy avenue for data injection attacks.  The Macros in an Excel document will continue to work until they are sent to another PC.  They no longer flag it as a security risk and ask permission to run it.  They will instead just give the corrupted file error. The solution below works for this situation.


Opening new Microsoft Files with Macros:
For any MicroSoft File with Macros, download the file and save to either "downloads" or a memorable location.
 
Without Opening the file, Right click on the file name in the folder.  From the Dropdown, select "Properties" at the bottom.  At the bottom of the Properties menu, check "Unblock.  Click "OK."  Then open the file the normal way and "Enable Macros" in the normal fashion.  The file will open normally on your computer thereafter.