Corrupted File Error when writing to an Excel File

I have a query running from Toad for Data Analysts When I run it to a new file it works perfectly. A little over 403,000 of data from Banner. But when I run it to an existing excel file and send it to a specific sheet I get an error when I try to open my excel file with the now updated data.

The reason I have it load there, is I am using it to perform a basic Dashboard on a Summary Sheet. The data from 3 files on separate spreadsheets provide the numbers for my Dashboard.