diff --git a/Modules/CMakeDetermineSystem.cmake b/Modules/CMakeDetermineSystem.cmake
index 80db89c35f..dc26258eac 100644
--- a/Modules/CMakeDetermineSystem.cmake
+++ b/Modules/CMakeDetermineSystem.cmake
@@ -139,17 +139,24 @@ endif()
 # variables around so they can be used in CMakeLists.txt.
 # In all other cases, the host and target platform are the same.
 if(CMAKE_TOOLCHAIN_FILE)
-  # at first try to load it as path relative to the directory from which cmake has been run
-  include("${CMAKE_BINARY_DIR}/${CMAKE_TOOLCHAIN_FILE}" OPTIONAL RESULT_VARIABLE _INCLUDED_TOOLCHAIN_FILE)
-  if(NOT _INCLUDED_TOOLCHAIN_FILE)
-     # if the file isn't found there, check the default locations
-     include("${CMAKE_TOOLCHAIN_FILE}" OPTIONAL RESULT_VARIABLE _INCLUDED_TOOLCHAIN_FILE)
-  endif()
-
-  if(_INCLUDED_TOOLCHAIN_FILE)
-    set(CMAKE_TOOLCHAIN_FILE "${_INCLUDED_TOOLCHAIN_FILE}" CACHE FILEPATH "The CMake toolchain file" FORCE)
+  if(IS_ABSOLUTE "${CMAKE_TOOLCHAIN_FILE}" AND EXISTS "${CMAKE_TOOLCHAIN_FILE}")
+    # Normalize the absolute path.
+    set(CMAKE_TOOLCHAIN_FILE "${CMAKE_TOOLCHAIN_FILE}" CACHE FILEPATH "The CMake toolchain file" FORCE)
+    set(CMAKE_TOOLCHAIN_FILE "$CACHE{CMAKE_TOOLCHAIN_FILE}")
+    include("${CMAKE_TOOLCHAIN_FILE}" OPTIONAL RESULT_VARIABLE _INCLUDED_TOOLCHAIN_FILE)
   else()
-    message(FATAL_ERROR "Could not find toolchain file: ${CMAKE_TOOLCHAIN_FILE}")
+    # at first try to load it as path relative to the directory from which cmake has been run
+    include("${CMAKE_BINARY_DIR}/${CMAKE_TOOLCHAIN_FILE}" OPTIONAL RESULT_VARIABLE _INCLUDED_TOOLCHAIN_FILE)
+    if(NOT _INCLUDED_TOOLCHAIN_FILE)
+      # if the file isn't found there, check the default locations
+      include("${CMAKE_TOOLCHAIN_FILE}" OPTIONAL RESULT_VARIABLE _INCLUDED_TOOLCHAIN_FILE)
+    endif()
+    if(_INCLUDED_TOOLCHAIN_FILE)
+      set(CMAKE_TOOLCHAIN_FILE "${_INCLUDED_TOOLCHAIN_FILE}" CACHE FILEPATH "The CMake toolchain file" FORCE)
+    endif()
+  endif()
+  if(NOT _INCLUDED_TOOLCHAIN_FILE)
+    message(FATAL_ERROR "Could not find toolchain file:\n \"${CMAKE_TOOLCHAIN_FILE}\"")
   endif()
 endif()
 
diff --git a/Tests/RunCMake/CommandLine/RunCMakeTest.cmake b/Tests/RunCMake/CommandLine/RunCMakeTest.cmake
index 4f993585aa..9fda9eb5b1 100644
--- a/Tests/RunCMake/CommandLine/RunCMakeTest.cmake
+++ b/Tests/RunCMake/CommandLine/RunCMakeTest.cmake
@@ -264,6 +264,10 @@ function(run_Toolchain)
   run_cmake_with_options(toolchain-no-arg -S ${source_dir} --toolchain=)
   run_cmake_with_options(toolchain-valid-abs-path -S ${source_dir} --toolchain "${source_dir}/toolchain.cmake")
   run_cmake_with_options(toolchain-valid-rel-src-path -S ${source_dir} --toolchain=toolchain.cmake)
+  run_cmake_with_options(toolchain-D-abs-path -S ${source_dir} -DCMAKE_TOOLCHAIN_FILE=${source_dir}/toolchain.cmake)
+  if(CMAKE_HOST_UNIX AND NOT CMAKE_SYSTEM_NAME STREQUAL "CYGWIN" AND NOT CMAKE_SYSTEM_NAME STREQUAL "MSYS")
+    run_cmake_with_options(toolchain-D-slash-abs-path -S ${source_dir} -DCMAKE_TOOLCHAIN_FILE=/${source_dir}/toolchain.cmake)
+  endif()
 
   set(RunCMake_TEST_NO_CLEAN 1)
   set(binary_dir ${RunCMake_BINARY_DIR}/Toolchain-build)
@@ -274,7 +278,6 @@ function(run_Toolchain)
   # precedence over source dir
   file(WRITE ${binary_dir}/toolchain.cmake [=[
 set(CMAKE_SYSTEM_NAME Linux)
-set(toolchain_file binary_dir)
 ]=])
   run_cmake_with_options(toolchain-valid-rel-build-path -S ${source_dir} -B ${binary_dir} --toolchain toolchain.cmake)
 endfunction()
diff --git a/Tests/RunCMake/CommandLine/Toolchain/CMakeLists.txt b/Tests/RunCMake/CommandLine/Toolchain/CMakeLists.txt
index 80d42b828b..d49b6849a3 100644
--- a/Tests/RunCMake/CommandLine/Toolchain/CMakeLists.txt
+++ b/Tests/RunCMake/CommandLine/Toolchain/CMakeLists.txt
@@ -1,3 +1,3 @@
 cmake_minimum_required(VERSION 3.20)
 project(Toolchain LANGUAGES NONE)
-message(FATAL_ERROR "${toolchain_file}")
+message(STATUS "CMAKE_TOOLCHAIN_FILE='${CMAKE_TOOLCHAIN_FILE}'")
diff --git a/Tests/RunCMake/CommandLine/Toolchain/toolchain.cmake b/Tests/RunCMake/CommandLine/Toolchain/toolchain.cmake
index 719556c0af..99c23014a7 100644
--- a/Tests/RunCMake/CommandLine/Toolchain/toolchain.cmake
+++ b/Tests/RunCMake/CommandLine/Toolchain/toolchain.cmake
@@ -1,2 +1 @@
 set(CMAKE_SYSTEM_NAME Linux)
-set(toolchain_file source_dir)
diff --git a/Tests/RunCMake/CommandLine/toolchain-D-abs-path-stdout.txt b/Tests/RunCMake/CommandLine/toolchain-D-abs-path-stdout.txt
new file mode 100644
index 0000000000..753f00b5ad
--- /dev/null
+++ b/Tests/RunCMake/CommandLine/toolchain-D-abs-path-stdout.txt
@@ -0,0 +1 @@
+CMAKE_TOOLCHAIN_FILE='[^']*/Tests/RunCMake/CommandLine/Toolchain/toolchain\.cmake'
diff --git a/Tests/RunCMake/CommandLine/toolchain-D-slash-abs-path-stdout.txt b/Tests/RunCMake/CommandLine/toolchain-D-slash-abs-path-stdout.txt
new file mode 100644
index 0000000000..9e9781f38a
--- /dev/null
+++ b/Tests/RunCMake/CommandLine/toolchain-D-slash-abs-path-stdout.txt
@@ -0,0 +1 @@
+CMAKE_TOOLCHAIN_FILE='/[^/][^']*/Tests/RunCMake/CommandLine/Toolchain/toolchain\.cmake'
diff --git a/Tests/RunCMake/CommandLine/toolchain-valid-abs-path-result.txt b/Tests/RunCMake/CommandLine/toolchain-valid-abs-path-result.txt
deleted file mode 100644
index d00491fd7e..0000000000
--- a/Tests/RunCMake/CommandLine/toolchain-valid-abs-path-result.txt
+++ /dev/null
@@ -1 +0,0 @@
-1
diff --git a/Tests/RunCMake/CommandLine/toolchain-valid-abs-path-stderr.txt b/Tests/RunCMake/CommandLine/toolchain-valid-abs-path-stderr.txt
deleted file mode 100644
index 21d5db6464..0000000000
--- a/Tests/RunCMake/CommandLine/toolchain-valid-abs-path-stderr.txt
+++ /dev/null
@@ -1 +0,0 @@
-^CMake Error.*source_dir
diff --git a/Tests/RunCMake/CommandLine/toolchain-valid-abs-path-stdout.txt b/Tests/RunCMake/CommandLine/toolchain-valid-abs-path-stdout.txt
new file mode 100644
index 0000000000..753f00b5ad
--- /dev/null
+++ b/Tests/RunCMake/CommandLine/toolchain-valid-abs-path-stdout.txt
@@ -0,0 +1 @@
+CMAKE_TOOLCHAIN_FILE='[^']*/Tests/RunCMake/CommandLine/Toolchain/toolchain\.cmake'
diff --git a/Tests/RunCMake/CommandLine/toolchain-valid-rel-build-path-result.txt b/Tests/RunCMake/CommandLine/toolchain-valid-rel-build-path-result.txt
deleted file mode 100644
index d00491fd7e..0000000000
--- a/Tests/RunCMake/CommandLine/toolchain-valid-rel-build-path-result.txt
+++ /dev/null
@@ -1 +0,0 @@
-1
diff --git a/Tests/RunCMake/CommandLine/toolchain-valid-rel-build-path-stderr.txt b/Tests/RunCMake/CommandLine/toolchain-valid-rel-build-path-stderr.txt
deleted file mode 100644
index 047554673f..0000000000
--- a/Tests/RunCMake/CommandLine/toolchain-valid-rel-build-path-stderr.txt
+++ /dev/null
@@ -1,2 +0,0 @@
-^CMake Error at CMakeLists.txt:[0-9] \(message\):
-  binary_dir$
diff --git a/Tests/RunCMake/CommandLine/toolchain-valid-rel-build-path-stdout.txt b/Tests/RunCMake/CommandLine/toolchain-valid-rel-build-path-stdout.txt
new file mode 100644
index 0000000000..659cf5fdea
--- /dev/null
+++ b/Tests/RunCMake/CommandLine/toolchain-valid-rel-build-path-stdout.txt
@@ -0,0 +1 @@
+CMAKE_TOOLCHAIN_FILE='[^']*/Tests/RunCMake/CommandLine/Toolchain-build/toolchain\.cmake'
diff --git a/Tests/RunCMake/CommandLine/toolchain-valid-rel-src-path-result.txt b/Tests/RunCMake/CommandLine/toolchain-valid-rel-src-path-result.txt
deleted file mode 100644
index d00491fd7e..0000000000
--- a/Tests/RunCMake/CommandLine/toolchain-valid-rel-src-path-result.txt
+++ /dev/null
@@ -1 +0,0 @@
-1
diff --git a/Tests/RunCMake/CommandLine/toolchain-valid-rel-src-path-stderr.txt b/Tests/RunCMake/CommandLine/toolchain-valid-rel-src-path-stderr.txt
deleted file mode 100644
index 21d5db6464..0000000000
--- a/Tests/RunCMake/CommandLine/toolchain-valid-rel-src-path-stderr.txt
+++ /dev/null
@@ -1 +0,0 @@
-^CMake Error.*source_dir
diff --git a/Tests/RunCMake/CommandLine/toolchain-valid-rel-src-path-stdout.txt b/Tests/RunCMake/CommandLine/toolchain-valid-rel-src-path-stdout.txt
new file mode 100644
index 0000000000..753f00b5ad
--- /dev/null
+++ b/Tests/RunCMake/CommandLine/toolchain-valid-rel-src-path-stdout.txt
@@ -0,0 +1 @@
+CMAKE_TOOLCHAIN_FILE='[^']*/Tests/RunCMake/CommandLine/Toolchain/toolchain\.cmake'