Sometimes Xcode project file easily gets messed up. For example, when I try to rebuild my application that worked well with my previous provisioning file yesterday, however I reinstall my provisioning file today. In this case, following error message can be show up;
"Code Sign Error: Provisioning Profile (long string) can't be found."
Here is an easy solution.
1) Open the project file in a text editor:
The .xcodeproj file is actually not a file but a directory, like an application bundle. So, you can right click it in Finder to open. Then, select "package contents". Now, you will see several files. The actual project file is "project.pbxproj". Open it in a text editor.
2) Search provisioning profile setting and manually erase the lines. Save the project file:
They will look like these;
PROVISIONING_PROFILE = "xxxxxx.....xxxxx";
"PROVISIONING_PROFILE[sdk=iphoneos*]" = "xxxxxx.....xxxxx";
3) Reopen the project in Xcode and go to the settings to reselect your new provisioning profile.