Command /Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang failed with exit code 1

I'm trying to do an application reading pdf using pdf kit in Xcode 4.3 but it gives me the following error

ld: duplicate symbol _OBJC_METACLASS_$_OverlayManager in /Users/dt4it/Library/Developer/Xcode/DerivedData/MyPdf4-bmkjglhhvneluqcbwpceiqjvdcmq/Build/Intermediates/MyPdf4.build/Debug-iphonesimulator/MyPdf4.build/Objects-normal/i386/OverlayManager-D0866CFD31A05E68.o and /Users/dt4it/Library/Developer/Xcode/DerivedData/MyPdf4-bmkjglhhvneluqcbwpceiqjvdcmq/Build/Intermediates/MyPdf4.build/Debug-iphonesimulator/MyPdf4.build/Objects-normal/i386/OverlayManager-B31AE7412100AF6D.o for architecture i386
Command /Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang failed with exit code 1

any help please ??

Project Settings > Under "Targets", select your project > Build Phases > open "Compile Sources" and "Copy Bundle Resources". Check if any files are listed in red color. If so , just delete it. Then clean and run.

Worked for me.

Do a clean. product > clean . Terminal purge & reboot didn't work for me, cleaning did.

I had this same error and nobody seems to have an answer on StackOverflow that actually works. My problem was when I tried copying a project that was in a team repository. Turns out, in the ignore file, all files with the extension of *.pch were ignored from repository commits. This means that when I went to pull the project from the repo, the .pch file was missing, thus throwing this error.

Fortunately I had a copy of the project still and was able to just copy the .pch file over and I was then able to compile just fine.

Hope this helps?