diff --git a/scripts/cmake/ExternalProjectBoost.cmake b/scripts/cmake/ExternalProjectBoost.cmake
index 71d4daef9e8d9e7172dff2236515300a16333d05..1f774322385545d8be5e74e72ba3aeb11c5b9a34 100644
--- a/scripts/cmake/ExternalProjectBoost.cmake
+++ b/scripts/cmake/ExternalProjectBoost.cmake
@@ -13,7 +13,7 @@ if(Boost_FOUND)
 endif()
 
 if(NOT DEFINED BOOST_ROOT AND DEFINED ENV{BOOST_ROOT})
-    set(BOOST_ROOT $ENV{BOOST_ROOT} TRUE CACHE PATH "")
+    set(BOOST_ROOT $ENV{BOOST_ROOT} CACHE PATH "")
 endif()
 
 # First check for system boost