I have a new Windows 8.1 computer. When I try to open a spreadsheet that is attached to an email, it takes 5-8 minutes for Excel to open the file. A banner at the top says it is opening in Protected View, and is extremely painful and slow.
Try turning off Protected View. You'll need to make this change in Excel's (and/or Word's) Trust Center, not within Outlook.
- Open Excel (or Word)
- Go to File, Options, Trust Center and click on Trust Center Settings.
- Select Protected View on the left.
- Uncheck Enable Protected View for Outlook attachments
Published May 29, 2015. Last updated on May 28, 2015.