TFS Build failed - Access to the path is denied

PROBLEM:
TFS Build failed when trying to build project because of the following error:

Copying file
C:\Builds\Agent\MyPrj\Binaries\Abc.Client.Silverlight.xap failed.
Access to the path 'C:\Builds\Agent\MyPrj\Sources\Dev\Abc.Client.Silverlight.Web\ClientBin\Abc.Client.Silverlight.xap'
is denied

SOLUTION:
Open your TFS source control in your Silverlight project ClientBin directory and check you didn't checked-in your xap files (in this case: Abc.Client.Silverlight.xap). If checked-in, delete it from the source control.
This error can occur in other projects types (not only Silverlight) when you checked-in files in a build deployment folder. Those files are copied into the build server as Read Only and cannot be overwritten later when the build server trying to deploy them

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