diff --git a/ci/test.windows.gitlab-ci.yml b/ci/test.windows.gitlab-ci.yml
index a7a66fa8175c490c2094bd65ed7b07e7d033af73..f107d4f496330c8c031c43d6ddb6e0427fee7cb5 100644
--- a/ci/test.windows.gitlab-ci.yml
+++ b/ci/test.windows.gitlab-ci.yml
@@ -10,7 +10,7 @@
     - if: $CI_PIPELINE_SOURCE == "web" && $CI_PROJECT_NAMESPACE == "libeigen"
     - if: $CI_PIPELINE_SOURCE == "merge_request_event" && $CI_PROJECT_NAMESPACE == "libeigen" && $CI_MERGE_REQUEST_LABELS =~ "/all-tests/"
 
-  tags: 
+  tags:
     - eigen-runner
     - windows
     - x86-64
@@ -64,7 +64,7 @@ test:windows:x86-64:msvc-14.29:avx2:unsupported:
 .test:windows:x86-64:msvc-14.29:avx512dq:
   extends: .test:windows
   needs: [ build:windows:x86-64:msvc-14.29:avx512dq ]
-  tags: 
+  tags:
     - eigen-runner
     - windows
     - x86-64
@@ -86,7 +86,7 @@ test:windows:x86-64:msvc-14.29:avx512dq:unsupported:
   allow_failure: true
   variables:
     EIGEN_CI_CTEST_LABEL: gpu
-  tags: 
+  tags:
     - eigen-runner
     - windows
     - x86-64
@@ -97,12 +97,12 @@ test:windows:x86-64:msvc-14.29:avx512dq:unsupported:
 # test:windows:x86-64:cuda-9.2:msvc-14.16:
 #   extends: .test:windows:cuda
 #   needs: [ build:windows:x86-64:cuda-9.2:msvc-14.16 ]
-  
+
 # MSVC 14.29 + CUDA 10.2
 test:windows:x86-64:cuda-10.2:msvc-14.29:
   extends: .test:windows:cuda
   needs: [ build:windows:x86-64:cuda-10.2:msvc-14.29 ]
-  
+
 # MSVC 14.29 + CUDA 11.4
 test:windows:x86-64:cuda-11.4:msvc-14.29:
   extends: .test:windows:cuda
diff --git a/cmake/EigenConfigureTesting.cmake b/cmake/EigenConfigureTesting.cmake
index eecef238678b69f29ea8ff11be9a4798de30bac1..d72d88a020f6375637ae515e393cc04648e21ec5 100644
--- a/cmake/EigenConfigureTesting.cmake
+++ b/cmake/EigenConfigureTesting.cmake
@@ -2,7 +2,7 @@ include(EigenTesting)
 include(CheckCXXSourceCompiles)
 
 
-# configure the "site" and "buildname" 
+# configure the "site" and "buildname"
 ei_set_sitename()
 
 # retrieve and store the build string
@@ -12,11 +12,7 @@ add_custom_target(buildtests)
 
 if (NOT EIGEN_CTEST_ARGS)
   # By default, run tests in parallel on all available cores.
-  include(ProcessorCount)
-  ProcessorCount(NPROC)
-  if(NOT NPROC EQUAL 0)
-    set(EIGEN_CTEST_ARGS "" CACHE STRING "-j"${NPROC})
-  endif()
+  set(EIGEN_CTEST_ARGS "" CACHE STRING "-j0")
 endif()
 add_custom_target(check COMMAND "ctest" ${EIGEN_CTEST_ARGS})
 
@@ -24,7 +20,7 @@ add_dependencies(check buildtests)
 
 # Convenience target for only building GPU tests.
 add_custom_target(buildtests_gpu)
-add_custom_target(check_gpu COMMAND "ctest" "--output-on-failure" 
+add_custom_target(check_gpu COMMAND "ctest" "--output-on-failure"
                                             "--no-compress-output"
                                             "--build-no-clean"
                                             "-T" "test"
@@ -70,7 +66,7 @@ if(CMAKE_COMPILER_IS_GNUCXX)
     set(CTEST_CUSTOM_COVERAGE_EXCLUDE "/test/")
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${COVERAGE_FLAGS}")
   endif()
-  
+
 elseif(MSVC)
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /D_CRT_SECURE_NO_WARNINGS /D_SCL_SECURE_NO_WARNINGS")
 endif()