Microsoft has unveiled several new features and capabilities that are coming to Excel on the web this month.

Restricted File Types Excel blocks input and output access to select file types on the basis of their formats' potential vulnerability to incorporating malware and other hacking exploits.

The Redmond, Wash., software maker published a prepatch advisory on June 19 with a list of workarounds that include blocking Excel file types at the e-mail gateway.

This also happens when Excel is not set as the default program for these file types. Under these circumstances, Windows tries to open the file with its own built-in alternatives.