Untrusted Project Location When Opening Solution

I downloaded source from a CodePlex project last night.  After unzipping the source to my hard drive and opening the solution I was bombarded with errors of The project location is not trusted: c:\... Running the application may result in security exceptions when it attempts to perform actions which require full trust."  I had to click OK for the solution and once for each project file.

Searching the web I ran across Colin Mackay's blog with a post explaining since Windows XP Service Pack 2 when downloading zip files an Alternate Data Streams (ADS) with a zone identifier are added in NTFS.  During unzipping the zone identifier is propagated to the solution and project files.  As Colin explains there are programs which can remove the ADS zone identifier.  I found out the best way to resolve this without downloading a tool is to right click on the properties of the archive, and at the bottom of the properties dialog in the security section click the Unblock button.  Then when the archive is unzipped the solution and project files won't have a zone identifier included.  One can also click the unblock button on each project and solution file after unzipping although this isn't as efficient.