Value <unsupported> should not appear in CMake platform & Toolset

Bad platform <unsupported> with "Visual Studio 16 2019" (MSBuild) :Running C:\Qt\Tools\CMake_64\bin\cmake.exe -S C:/dev/untitled4 -B C:/dev/build-untitled4-Desktop_Qt_5_15_1_MSVC2019_64bit-Debug "-A<unsupported>" "-T<unsupported>" "-GVisual Studio 16 2019" "-DCMAKE_BUILD_TYPE:String=Debug" "-DQT_QMAKE_EXECUTABLE:STRING=C:/Qt/5.15.1/msvc2019_64/bin/qmake.exe" "-DCMAKE_PREFIX_PATH:STRING=C:/Qt/5.15.1/msvc2019_64" "-DCMAKE_C_COMPILER:STRING=C:/Program Files (x86)/Microsoft Visual Studio/2019/Community/VC/Tools/MSVC/14.27.29110/bin/HostX64/x64/cl.exe" "-DCMAKE_CXX_COMPILER:STRING=C:/Program Files (x86)/Microsoft Visual Studio/2019/Community/VC/Tools/MSVC/14.27.29110/bin/HostX64/x64/cl.exe" in C:\dev\build-untitled4-Desktop_Qt_5_15_1_MSVC2019_64bit-Debug.
-- Selecting Windows SDK version 10.0.17763.0 to target Windows 10.0.18363.
CMake Error at CMakeLists.txt:3 (project):
  Failed to run MSBuild command:    C:/Program Files (x86)/Microsoft Visual Studio/2019/Community/MSBuild/Current/Bin/MSBuild.exe  to get the value of VCTargetsPath:    Microsoft (R) Build Engine version 16.7.0+b89cb5fde pour .NET Framework
    Copyright (C) Microsoft Corporation. Tous droits réservés.
    
    La génération a démarré 30/10/2020 23:58:20.
    Projet "C:\dev\build-untitled4-Desktop_Qt_5_15_1_MSVC2019_64bit-Debug\CMakeFiles\3.18.3\VCTargetsPath.vcxproj" sur le noud 1 (cibles par défaut).
    C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\MSBuild\Current\Bin\Microsoft.Common.CurrentVersion.targets(3293,5): error MSB4184: impossible d'évaluer l'expression "[System.IO.Path]::Combine(obj\<unsupported>\Debug\, .NETFramework,Version=v4.0.AssemblyAttributes.cpp)". Caractères non conformes dans le chemin d'accès. [C:\dev\build-untitled4-Desktop_Qt_5_15_1_MSVC2019_64bit-Debug\CMakeFiles\3.18.3\VCTargetsPath.vcxproj]
    Génération du projet "C:\dev\build-untitled4-Desktop_Qt_5_15_1_MSVC2019_64bit-Debug\CMakeFiles\3.18.3\VCTargetsPath.vcxproj" terminée (cibles par défaut) -- ÉCHEC.
    
    ÉCHEC de la build.
    
    "C:\dev\build-untitled4-Desktop_Qt_5_15_1_MSVC2019_64bit-Debug\CMakeFiles\3.18.3\VCTargetsPath.vcxproj" (cible par défaut) (1) ->
      C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\MSBuild\Current\Bin\Microsoft.Common.CurrentVersion.targets(3293,5): error MSB4184: impossible d'évaluer l'expression "[System.IO.Path]::Combine(obj\<unsupported>\Debug\, .NETFramework,Version=v4.0.AssemblyAttributes.cpp)". Caractères non conformes dans le chemin d'accès. [C:\dev\build-untitled4-Desktop_Qt_5_15_1_MSVC2019_64bit-Debug\CMakeFiles\3.18.3\VCTargetsPath.vcxproj]
    
        0 Avertissement(s)
        1 Erreur(s)
    
    Temps écoulé 00:00:00.06
      Exit code: 1