Protected View

Hi,

I'm a user of Excel 2010 and have recently downloaded from a publisher's website the sample Excel files to accompany the book I've just bought.

Because these files "originated from an internet location and might be unsafe", Excel opens the file in Protected View and I need to click "Enable Editing" if I wish to edit the worksheet. Some of the files are .xlsx and others .xlsm.

What, if any, checks should I run on these files before I "enable editing"?

Thanks