I upgraded to Win10 in June. I run Office Pro 2013. Since the Win10 upgrade workbooks open agonizingly slow when I double click one in file explorer if Excel isn't running already. It takes more than 1 minute before the Excel splash screen displays even. If I open Excel directly, it opens quickly. If I then double click an Excel file in File Explorer it also opens very quickly. Slow opening as described wasn't an issue when I was running Win 8.1. Word files and pdf files and others don't have this issue, only Excel files, either xls or xlsx. Any thoughts? Suggestions?

Molechaser