Corrupted XML when trying to import data in CRM Online

Scenario: You try to import data into Dynamics CRM Online (2011) and you choose the option to download a XML Template - "Download Template for Import".
An error pops up in Excel saying that the file is corrupt: "The file is corrupt and cannot be opened"

There's no problem with the file itself, but with a security setting in Excel.

The solution is to save the file in a specific location (for example Desktop\crm) and add this location to the Trusted Locations in Excel:
- Excel -> File -> Options -> Trust Center -> Trust Center Settings ... -> Trusted Locations