Have a Sony Vaio 11 with Windows 8 Pro.

When I try to open any Excel or Word document saved on my Skydrive account I receive the following message: "We're sorry, we couldn't open your workbook. It's possibly corrupt or using a file format that's not supported. Do you want to try and open this file in Excel?"

I then receive the following message when I attempt to open the file using my desktop application of Excel:

"We're sorry. We can't open the file because we found a problem with its contents."

The issue started on September 19th 2013. Any file saved post the 19th are fully accessible and without issue.

All other files including Adobe Photoshop, PowerPointe and wiebsite shortcuts open without issue.

Thoughts for resolution?

Thanks.