How can I build someone else's Xcode project?

I was given a project folder which contains an Xcode project along with all the source files. When I open the Xcode project, and build it, it gave me this error:

"The executable was signed with invalid entitlements"

How can I change the project such that my own provisioning profile will work? It should be possible because I have opened Xcode projects before and was able to build it straight to my phone.

Edit:

Code signing entitlements is blank
This is not an ad-hoc build. It is debug and I am copy/pasting someone else's folder which contains the Xcode project and files.

Solution

Check that sign identity, entitlements, etc. is properly set for both the Project and the Target. Preferably delete the setting for the Target and only define for the Project.