title: Swift stdlib tool Error
body: <p>I'm getting this error on compilation with Xcode 8.1 and Swift 3:</p>
  
  <blockquote>
    <p>Swift stdlib tool Error</p>
  </blockquote>
  
  <p>The end of the compile log looks like:</p>
  
  <pre><code>/Users/..../Library/Developer/Xcode/DerivedData/.../Build/Products/Debug/.../Contents/Frameworks/libswiftCore.dylib: replacing existing signature
  /Users/..../Library/Developer/Xcode/DerivedData/.../Build/Products/Debug/.../Contents/Frameworks/libswiftCore.dylib: CSSMERR_CSP_INVALID_CONTEXT_HANDLE
  In architecture: x86_64
  Probing signature of /Users/..../Library/Developer/Xcode/DerivedData/.../Build/Products/Debug/.../Contents/Frameworks/libswiftXPC.dylib
    /usr/bin/codesign '-r-' '--display' '/Users/..../Library/Developer/Xcode/DerivedData/.../Build/Products/Debug/.../Contents/Frameworks/libswiftXPC.dylib'
  error: Task failed with exit 1 signal 0 {
      /usr/bin/codesign '--force' '--sign' '-' '--verbose' '/Users/..../Library/Developer/Xcode/DerivedData/.../Build/Products/Debug/.../Contents/Frameworks/libswiftCore.dylib'
  }
  </code></pre>
  
  <p>The very strange thing is that if I copy the folder with the project to my Desktop, it does compile without the error. If I copy it elsewhere, it errors. Moving it back and forth a couple of times to verify, finally after the third move, it's erroring on the Desktop as well.</p>
  
  <p>Any ideas?</p>
  
  <p>Many thanks in advance.</p>