# failed to generate fastbuild

**URL:** https://discourse.cmake.org/t/failed-to-generate-fastbuild/15378
**Category:** Usage
**Tags:** os:windows
**Created:** [December 9, 2025, 11:58am UTC](https://discourse.cmake.org/t/failed-to-generate-fastbuild/15378 "2025-12-09T11:58:07Z")
**Posts on this page:** 3
**Page:** 1

<div class="post-metadata">

### Author: ![TimeLooper](https://discourse.cmake.org/user_avatar/discourse.cmake.org/timelooper/32/5936_2.png) [@TimeLooper](https://discourse.cmake.org/u/TimeLooper)
#### Post date: [December 9, 2025, 11:58am UTC](https://discourse.cmake.org/t/failed-to-generate-fastbuild/15378/1 "2025-12-09T11:58:07Z")

</div>

CMake Error at C:/Program Files/CMake/share/cmake-4.2/Modules/CMakeTestCCompiler.cmake:67 (message):  
The C compiler

```auto
"C:/Program Files (x86)/Microsoft Visual Studio/2019/Community/VC/Tools/MSVC/14.29.30133/bin/Hostx64/x64/cl.exe"

```

is not able to compile a simple test program.

It fails with the following output:

```auto
Change Dir: 'D:/repos/cmake/build/CMakeFiles/CMakeScratch/TryCompile-qbhvdj'

Run Build Command(s): C:/PROGRA~1/FASTBU~1/FBuild.exe -config D:/repos/cmake/build/CMakeFiles/CMakeScratch/TryCompile-qbhvdj/fbuild.bff -continueafterdbmove -showcmdoutput cmTC_d55b3 -verbose
Loading BFF 'D:\repos\cmake\build\CMakeFiles\CMakeScratch\TryCompile-qbhvdj\fbuild.bff'
Concurrency Group: 'Utils'
 - Limit: 1
 - MiB : 0
 - Final: 1
Additional library 'kernel32.lib' assumed to be 'C:\Program Files (x86)\Windows Kits\10\lib\10.0.26100.0\um\x64\kernel32.lib'
Additional library 'user32.lib' assumed to be 'C:\Program Files (x86)\Windows Kits\10\lib\10.0.26100.0\um\x64\user32.lib'
Additional library 'gdi32.lib' assumed to be 'C:\Program Files (x86)\Windows Kits\10\lib\10.0.26100.0\um\x64\gdi32.lib'
Additional library 'winspool.lib' assumed to be 'C:\Program Files (x86)\Windows Kits\10\lib\10.0.26100.0\um\x64\winspool.lib'
Additional library 'shell32.lib' assumed to be 'C:\Program Files (x86)\Windows Kits\10\lib\10.0.26100.0\um\x64\shell32.lib'
Additional library 'ole32.lib' assumed to be 'C:\Program Files (x86)\Windows Kits\10\lib\10.0.26100.0\um\x64\ole32.lib'
Additional library 'oleaut32.lib' assumed to be 'C:\Program Files (x86)\Windows Kits\10\lib\10.0.26100.0\um\x64\oleaut32.lib'
Additional library 'uuid.lib' assumed to be 'C:\Program Files (x86)\Windows Kits\10\lib\10.0.26100.0\um\x64\uuid.lib'
Additional library 'comdlg32.lib' assumed to be 'C:\Program Files (x86)\Windows Kits\10\lib\10.0.26100.0\um\x64\comdlg32.lib'
Additional library 'advapi32.lib' assumed to be 'C:\Program Files (x86)\Windows Kits\10\lib\10.0.26100.0\um\x64\advapi32.lib'
1> -Build: 0 ms C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.29.30133\bin\Hostx64\x64\atlprov.dll
1> -Build: 0 ms C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.29.30133\bin\Hostx64\x64\c2.dll
1> -Build: 0 ms C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.29.30133\bin\Hostx64\x64\c1xx.dll
1> -Build: 0 ms C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.29.30133\bin\Hostx64\x64\c1.dll
1> -Build: 0 ms C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.29.30133\bin\Hostx64\x64\cl.exe
1> -Build: 0 ms C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.29.30133\bin\Hostx64\x64\tbbmalloc.dll
1> -Build: 0 ms C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.29.30133\bin\Hostx64\x64\msvcp140_atomic_wait.dll
1> -Build: 0 ms C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.29.30133\bin\Hostx64\x64\msvcp140.dll
1> -Build: 0 ms C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.29.30133\bin\Hostx64\x64\mspft140.dll
1> -Build: 0 ms C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.29.30133\bin\Hostx64\x64\mspdbsrv.exe
1> -Build: 0 ms D:\repos\cmake\build\CMakeFiles\CMakeScratch\TryCompile-qbhvdj\testCCompiler.c
1> -Build: 0 ms C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.29.30133\bin\Hostx64\x64\1033\mspft140ui.dll
1> -Build: 0 ms C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.29.30133\bin\Hostx64\x64\1033\clui.dll
3> -Build: 0 ms C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.29.30133\bin\Hostx64\x64\vcruntime140_1.dll
1> -Build: 0 ms C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.29.30133\bin\Hostx64\x64\vcruntime140.dll
3> -Build: 0 ms C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.29.30133\bin\Hostx64\x64\mspdbcore.dll
1> -Build: 0 ms C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.29.30133\bin\Hostx64\x64\mspdb140.dll
3> -Build: 0 ms C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.29.30133\bin\Hostx64\x64\msobj140.dll
1> -Build: 0 ms C:\Program Files (x86)\Windows Kits\10\lib\10.0.26100.0\um\x64\shell32.lib
3> -Build: 0 ms C:\Program Files (x86)\Windows Kits\10\lib\10.0.26100.0\um\x64\kernel32.lib
3> -Build: 0 ms C:\Program Files (x86)\Windows Kits\10\lib\10.0.26100.0\um\x64\winspool.lib
3> -Build: 0 ms C:\Program Files (x86)\Windows Kits\10\lib\10.0.26100.0\um\x64\gdi32.lib
4> -Build: 0 ms C:\Program Files (x86)\Windows Kits\10\lib\10.0.26100.0\um\x64\user32.lib
3> -Build: 0 ms C:\Program Files (x86)\Windows Kits\10\lib\10.0.26100.0\um\x64\advapi32.lib
4> -Build: 0 ms C:\Program Files (x86)\Windows Kits\10\lib\10.0.26100.0\um\x64\comdlg32.lib
3> -Build: 0 ms C:\Program Files (x86)\Windows Kits\10\lib\10.0.26100.0\um\x64\uuid.lib
4> -Build: 0 ms C:\Program Files (x86)\Windows Kits\10\lib\10.0.26100.0\um\x64\oleaut32.lib
3> -Build: 0 ms C:\Program Files (x86)\Windows Kits\10\lib\10.0.26100.0\um\x64\ole32.lib
4> -Build: 0 ms C:\PROGRA~2\MIB055~1\2019\COMMUN~1\VC\Tools\MSVC\1429~1.301\bin\Hostx64\x64\link.exe
1> Error: opening file 'C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.29.30133\bin\Hostx64\x64\1033\clui.dll' in Compiler ToolManifest. File not found.
Saving DepGraph 'D:/repos/cmake/build/CMakeFiles/CMakeScratch/TryCompile-qbhvdj/fbuild.windows.fdb'
Saving DepGraph Complete in 0.000s
FBuild: Error: BUILD FAILED: cmTC_d55b3
Time: 0.016s

```

CMake will not be able to correctly generate this project.  
Call Stack (most recent call first):  
CMakeLists.txt:12 (project)

---

<div class="post-metadata">

### Author: ![ben.boeckel](https://discourse.cmake.org/letter_avatar_proxy/v4/letter/b/ea5d25/32.png) [@ben.boeckel](https://discourse.cmake.org/u/ben.boeckel)
#### Post date: [February 9, 2026, 5:08am UTC](https://discourse.cmake.org/t/failed-to-generate-fastbuild/15378/2 "2026-02-09T05:08:58Z")

</div>

@Eduard_Voronkin Looks like FASTBuild here. Is this known/fixed?

---

<div class="post-metadata">

### Author: ![Eduard\_Voronkin](https://discourse.cmake.org/user_avatar/discourse.cmake.org/eduard_voronkin/32/5873_2.png) [@Eduard\_Voronkin](https://discourse.cmake.org/u/Eduard_Voronkin)
#### Post date: [February 15, 2026, 10:54pm UTC](https://discourse.cmake.org/t/failed-to-generate-fastbuild/15378/3 "2026-02-15T22:54:14Z")

</div>

I originally made an easy fix here: [https://gitlab.kitware.com/cmake/cmake/-/merge\_requests/11557](https://gitlab.kitware.com/cmake/cmake/-/merge_requests/11557) (it allows CMake to configure when `CMAKE_FASTBUILD_COMPILER_EXTRA_FILES`is set), but ultimately it should be fixed by this MR: [https://gitlab.kitware.com/cmake/cmake/-/merge\_requests/11668](https://gitlab.kitware.com/cmake/cmake/-/merge_requests/11668)