title: Xamarin iOS Linking Failed Problem While Building
body: <p>The application is ready for Xamarin IOS.
  Yesterday there was no problem. I did visual studio update for hot restart to 16.7.3.
  Today when I turn it on, I am remote to the mac, but when I say build, I get linking failed errors like the following, about 33.
  I haven't installed any nuget packages etc.
  <strong>It took me a day to undo the last changes I made.
  It builds when not connected to the Mac but when I connect to the mac I get these errors anyway.
  I can't figure it out. Can you help me?</strong></p>
  <p>This is the project output while building:</p>
  <pre><code>2&gt;  takikuyumculuk.iOS -&gt; C:\Users\Onur\source\repos\takikuyumculuk\takikuyumculuk\takikuyumculuk.iOS\bin\iPhoneSimulator\Release\takikuyumculuk.iOS.exe
  2&gt;  Detected signing identity:
  2&gt;          
  2&gt;    Bundle Id: com.takikuyumculuk.apple
  2&gt;    App Id: com.takikuyumculuk.apple
  2&gt;  /Library/Frameworks/Xamarin.iOS.framework/Versions/Current/bin/mtouch @/Users/takikuyumculuk/Library/Caches/Xamarin/mtbs/builds/takikuyumculuk.iOS/9d7e2ac1ac9741d6ee40a3186654ad40/obj/iPhoneSimulator/Release/response-file.rsp &quot;--gcc_flags=-ObjC -lc++ -lsqlite3 -lz&quot; 
  2&gt;C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(884,3): error MT5210: Native linking failed, undefined symbol: _GULIsLoggableLevel. Please verify that all the necessary frameworks have been referenced and native libraries are properly linked in.
  2&gt;C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(884,3): error MT5210: Native linking failed, undefined symbol: _GULLogBasic. Please verify that all the necessary frameworks have been referenced and native libraries are properly linked in.
  2&gt;C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(884,3): error MT5210: Native linking failed, undefined symbol: _GULLogError. Please verify that all the necessary frameworks have been referenced and native libraries are properly linked in.
  2&gt;C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(884,3): error MT5210: Native linking failed, undefined symbol: _GULLogInfo. Please verify that all the necessary frameworks have been referenced and native libraries are properly linked in.
  2&gt;C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(884,3): error MT5210: Native linking failed, undefined symbol: _GULLogWarning. Please verify that all the necessary frameworks have been referenced and native libraries are properly linked in.
  2&gt;C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(884,3): error MT5210: Native linking failed, undefined symbol: _GULSetLoggerLevel. Please verify that all the necessary frameworks have been referenced and native libraries are properly linked in.
  2&gt;C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(884,3): error MT5211: Native linking failed, undefined Objective-C class: GULAppDelegateSwizzler. The symbol '_OBJC_CLASS_$_GULAppDelegateSwizzler' could not be found in any of the libraries or frameworks linked with your application.
  2&gt;C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(884,3): error MT5211: Native linking failed, undefined Objective-C class: GULAppEnvironmentUtil. The symbol '_OBJC_CLASS_$_GULAppEnvironmentUtil' could not be found in any of the libraries or frameworks linked with your application.
  2&gt;C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(884,3): error MT5211: Native linking failed, undefined Objective-C class: GULMutableDictionary. The symbol '_OBJC_CLASS_$_GULMutableDictionary' could not be found in any of the libraries or frameworks linked with your application.
  2&gt;C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(884,3): error MT5211: Native linking failed, undefined Objective-C class: GULNetwork. The symbol '_OBJC_CLASS_$_GULNetwork' could not be found in any of the libraries or frameworks linked with your application.
  2&gt;C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(884,3): error MT5211: Native linking failed, undefined Objective-C class: GULSwizzler. The symbol '_OBJC_CLASS_$_GULSwizzler' could not be found in any of the libraries or frameworks linked with your application.
  2&gt;C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(884,3): error MT5210: Native linking failed, undefined symbol: _kGULNetworkHTTPStatusCodeCannotAcceptTraffic. Please verify that all the necessary frameworks have been referenced and native libraries are properly linked in.
  2&gt;C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(884,3): error MT5210: Native linking failed, undefined symbol: _kGULNetworkHTTPStatusCodeNotFound. Please verify that all the necessary frameworks have been referenced and native libraries are properly linked in.
  2&gt;C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(884,3): error MT5210: Native linking failed, undefined symbol: _kGULNetworkHTTPStatusCodeNotModified. Please verify that all the necessary frameworks have been referenced and native libraries are properly linked in.
  2&gt;C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(884,3): error MT5210: Native linking failed, undefined symbol: _kGULNetworkHTTPStatusCodeUnavailable. Please verify that all the necessary frameworks have been referenced and native libraries are properly linked in.
  2&gt;C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(884,3): error MT5210: Native linking failed, undefined symbol: _kGULNetworkHTTPStatusNoContent. Please verify that all the necessary frameworks have been referenced and native libraries are properly linked in.
  2&gt;C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(884,3): error MT5210: Native linking failed, undefined symbol: _kGULNetworkHTTPStatusOK. Please verify that all the necessary frameworks have been referenced and native libraries are properly linked in.
  2&gt;C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(884,3): error MT5210: Native linking failed, undefined symbol: _pb_decode. Please verify that all the necessary frameworks have been referenced and native libraries are properly linked in.
  2&gt;C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(884,3): error MT5210: Native linking failed, undefined symbol: _pb_decode_varint. Please verify that all the necessary frameworks have been referenced and native libraries are properly linked in.
  2&gt;C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(884,3): error MT5210: Native linking failed, undefined symbol: _pb_encode. Please verify that all the necessary frameworks have been referenced and native libraries are properly linked in.
  2&gt;C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(884,3): error MT5210: Native linking failed, undefined symbol: _pb_encode_string. Please verify that all the necessary frameworks have been referenced and native libraries are properly linked in.
  2&gt;C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(884,3): error MT5210: Native linking failed, undefined symbol: _pb_encode_submessage. Please verify that all the necessary frameworks have been referenced and native libraries are properly linked in.
  2&gt;C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(884,3): error MT5210: Native linking failed, undefined symbol: _pb_encode_tag_for_field. Please verify that all the necessary frameworks have been referenced and native libraries are properly linked in.
  2&gt;C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(884,3): error MT5210: Native linking failed, undefined symbol: _pb_encode_varint. Please verify that all the necessary frameworks have been referenced and native libraries are properly linked in.
  2&gt;C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(884,3): error MT5210: Native linking failed, undefined symbol: _pb_istream_from_buffer. Please verify that all the necessary frameworks have been referenced and native libraries are properly linked in.
  2&gt;C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(884,3): error MT5210: Native linking failed, undefined symbol: _pb_ostream_from_buffer. Please verify that all the necessary frameworks have been referenced and native libraries are properly linked in.
  2&gt;C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(884,3): error MT5210: Native linking failed, undefined symbol: _pb_read. Please verify that all the necessary frameworks have been referenced and native libraries are properly linked in.
  2&gt;C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(884,3): warning MT5215: References to 'System' might require additional -framework=XXX or -lXXX instructions to the native linker
  2&gt;C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(884,3): warning MT5215: References to 'System' might require additional -framework=XXX or -lXXX instructions to the native linker
  2&gt;C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(884,3): warning MT5215: References to 'System' might require additional -framework=XXX or -lXXX instructions to the native linker
  2&gt;C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(884,3): warning MT5215: References to 'System.Net.Security' might require additional -framework=XXX or -lXXX instructions to the native linker
  2&gt;C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(884,3): warning MT5215: References to 'System' might require additional -framework=XXX or -lXXX instructions to the native linker
  2&gt;C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(884,3): warning MT5215: References to 'dl' might require additional -framework=XXX or -lXXX instructions to the native linker
  2&gt;C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(884,3): warning MT5215: References to 'kernel32' might require additional -framework=XXX or -lXXX instructions to the native linker
  2&gt;C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(884,3): warning MT5215: References to 'kernel32' might require additional -framework=XXX or -lXXX instructions to the native linker
  2&gt;C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(884,3): error MT5201: Native linking failed. Please review the build log and the user flags provided to gcc: -ObjC -lc++ -lsqlite3 -lz
  2&gt;C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(884,3): error : ] in GoogleAppMeasurement(APMMeasurement_87bdad44f2b9aa68c2d607a36be1b8c5.o)
  2&gt;C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(884,3): error : ] in GoogleAppMeasurement(APMMeasurement_87bdad44f2b9aa68c2d607a36be1b8c5.o)
  2&gt;C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(884,3): error : ] in GoogleAppMeasurement(APMMeasurement_87bdad44f2b9aa68c2d607a36be1b8c5.o)
  2&gt;C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(884,3): error : ] in GoogleAppMeasurement(APMMeasurement_87bdad44f2b9aa68c2d607a36be1b8c5.o)
  2&gt;C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(884,3): error : linker command failed with exit code 1 (use -v to see invocation)
  ========== Build: 1 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========
  ========== Deploy: 0 succeeded, 0 failed, 0 skipped ==========
  </code></pre>
  <p>This is the image of errors:</p>
  <p><a href="https://i.stack.imgur.com/Hpqt9.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Hpqt9.png" alt="enter image description here" /></a></p>