title: Xcode failed to emit precompiled header?
body: <p>thanks in advance for the help you will give me. </p>
  
  <p>I have searched this for half a day over the internet yesterday and two hours now and I haven't found anything (more than those two links that did not help <a href="https://stackoverflow.com/questions/15683180/fmdatabase-h-not-found-when-using-route-me-library">FMDatabase.h not found when using route-me library</a> &amp; <a href="https://stackoverflow.com/questions/45779591/failed-to-emit-precompiled-header-for-bridging-header/45878457">Failed to emit precompiled header for bridging header</a>)</p>
  
  <p>So here is my problem : I just had in hands a project that a previous developer has been working on, and when I try to launch it, here I have two errors : </p>
  
  <blockquote>
    <p>failed to emit precompiled header
    '/Users/me/Library/Developer/Xcode/DerivedData/Alavoc-arfzuirebtfstncdztyvgvtpcbgw/Build/Intermediates.noindex/PrecompiledHeaders/Alavoc-Bridging-Header-swift_1I75NH5N40QPS-clang_30E4RG2TSVLXF.pch'
    for bridging header
    '/Users/me/Downloads/Alavoc-ios-master/Alavoc/bridge/Alavoc-Bridging-Header.h'</p>
    
    <p>/Users/me/Downloads/Alavoc-ios-master/Alavoc/externalLib/customClass/customClassViewController.h:13:9:
    error: 'FMDB/FMDB.h' file not found</p>
  </blockquote>
  
  <p>There is also one fatal error wroten like this (even if I only have two errors counted, this one appears in the log above the two other ones previously described)</p>
  
  <blockquote>
    <p>fatal error: module file
    '/Users/me/Library/Developer/Xcode/DerivedData/ModuleCache/30E4RG2TSVLXF/Foundation-3DFYNEBRQSXST.pcm'
    is out of date and needs to be rebuilt: signature mismatch note:
    imported by
    '/Users/me/Library/Developer/Xcode/DerivedData/Alavoc-arfzuirebtfstncdztyvgvtpcbgw/Build/Intermediates.noindex/PrecompiledHeaders/Alavoc-Bridging-Header-swift_1I75NH5N40QPS-clang_30E4RG2TSVLXF.pch'
    /Users/me/Downloads/Alavoc-ios-master/Alavoc/bridge/Alavoc-Bridging-Header.h:13:9:
    note: in file included from
    /Users/me/Downloads/Alavoc-ios-master/Alavoc/bridge/Alavoc-Bridging-Header.h:13:
     #import "customClassViewController.h"</p>
  </blockquote>
  
  <p>customClassViewController.h line 13 : </p>
  
  <pre><code>#import &lt;FMDB/FMDB.h&gt;
  </code></pre>
  
  <p>I guess those errors are linked. Do you have any idea where it could come from ? </p>
  
  <p>Thanks in advance for your help guys, I really appreciate it!</p>
  
  <p><strong>Edit for battlmonster (new errors) :</strong></p>
  
  <p>Here are the two errros (file not found (in Alavoc-Bridging-Header.h FMDB.h not found)) and failed to emit precompiled header : </p>
  
  <blockquote>
    <p>fatal error: file
    '/Users/me/Downloads/Alavoc-ios-master/Alavoc/bridge/Alavoc-Bridging-Header.h'
    has been modified since the precompiled header
    '/Users/me/Library/Developer/Xcode/DerivedData/Alavoc-arfzuirebtfstncdztyvgvtpcbgw/Build/Intermediates.noindex/PrecompiledHeaders/Alavoc-Bridging-Header-swift_1I75NH5N40QPS-clang_30E4RG2TSVLXF.pch'
    was built note: please rebuild precompiled header
    '/Users/me/Library/Developer/Xcode/DerivedData/Alavoc-arfzuirebtfstncdztyvgvtpcbgw/Build/Intermediates.noindex/PrecompiledHeaders/Alavoc-Bridging-Header-swift_1I75NH5N40QPS-clang_30E4RG2TSVLXF.pch'
    /Users/me/Downloads/Alavoc-ios-master/Alavoc/bridge/Alavoc-Bridging-Header.h:29:9:
    error: 'FMDB/FMDB.h' file not found</p>
    
    <h1>import </h1>
  
  <pre><code>    ^ 1 error generated. &lt;unknown&gt;:0: error: failed to emit precompiled header
  </code></pre>
    
    <p>'/Users/me/Library/Developer/Xcode/DerivedData/Alavoc-arfzuirebtfstncdztyvgvtpcbgw/Build/Intermediates.noindex/PrecompiledHeaders/Alavoc-Bridging-Header-swift_1I75NH5N40QPS-clang_30E4RG2TSVLXF.pch'
    for bridging header
    '/Users/me/Downloads/Alavoc-ios-master/Alavoc/bridge/Alavoc-Bridging-Header.h'</p>
  </blockquote>