diff --git a/cmake/zlib.cmake b/cmake/zlib.cmake
index 5ca9f6d..86b9035 100644
--- a/cmake/zlib.cmake
+++ b/cmake/zlib.cmake
@@ -1,51 +1,8 @@
 # build Zlib to ensure compatibility.
 # We use Zlib 2.x for speed and robustness.
 include(GNUInstallDirs)
-include(ExternalProject)
 
-set(ZLIB_INCLUDE_DIRS ${CMAKE_INSTALL_PREFIX}/include)
-
-if(BUILD_SHARED_LIBS)
-  if(WIN32)
-    set(ZLIB_LIBRARIES ${CMAKE_INSTALL_PREFIX}/lib/${CMAKE_SHARED_LIBRARY_PREFIX}zlib1${CMAKE_SHARED_LIBRARY_SUFFIX})
-  else()
-    set(ZLIB_LIBRARIES ${CMAKE_INSTALL_PREFIX}/lib/${CMAKE_SHARED_LIBRARY_PREFIX}z${CMAKE_SHARED_LIBRARY_SUFFIX})
-  endif()
-else()
-  if(MSVC)
-    set(ZLIB_LIBRARIES ${CMAKE_INSTALL_PREFIX}/lib/${CMAKE_STATIC_LIBRARY_PREFIX}zlibstatic${CMAKE_STATIC_LIBRARY_SUFFIX})
-  else()
-    set(ZLIB_LIBRARIES ${CMAKE_INSTALL_PREFIX}/lib/${CMAKE_STATIC_LIBRARY_PREFIX}z${CMAKE_STATIC_LIBRARY_SUFFIX})
-  endif()
-endif()
-
-set(zlib_cmake_args
--DCMAKE_INSTALL_PREFIX:PATH=${CMAKE_INSTALL_PREFIX}
--DBUILD_SHARED_LIBS:BOOL=${BUILD_SHARED_LIBS}
--DCMAKE_BUILD_TYPE=Release
--DZLIB_COMPAT:BOOL=on
--DZLIB_ENABLE_TESTS:BOOL=off
--DCMAKE_POSITION_INDEPENDENT_CODE:BOOL=ON
--DCMAKE_C_COMPILER=${CMAKE_C_COMPILER}
-)
-
-ExternalProject_Add(ZLIB
-GIT_REPOSITORY https://github.com/zlib-ng/zlib-ng.git
-GIT_TAG 2.0.6
-GIT_SHALLOW true
-CMAKE_ARGS ${zlib_cmake_args}
-BUILD_BYPRODUCTS ${ZLIB_LIBRARIES}
-TLS_VERIFY true
-CONFIGURE_HANDLED_BY_BUILD ON
-INACTIVITY_TIMEOUT 60
-)
-
-# --- imported target
-
-file(MAKE_DIRECTORY ${ZLIB_INCLUDE_DIRS})
-# avoid race condition
+find_library(ZLIB_LIBRARIES NAMES z-ng)
 
 add_library(ZLIB::ZLIB INTERFACE IMPORTED GLOBAL)
-add_dependencies(ZLIB::ZLIB ZLIB)  # to avoid include directory race condition
 target_link_libraries(ZLIB::ZLIB INTERFACE ${ZLIB_LIBRARIES})
-target_include_directories(ZLIB::ZLIB INTERFACE ${ZLIB_INCLUDE_DIRS})