diff --git a/build/docker/msvc2017/build.bat b/build/docker/msvc2017/build.bat
index ac7b68a..018805b 100644
--- a/build/docker/msvc2017/build.bat
+++ b/build/docker/msvc2017/build.bat
@@ -28,6 +28,7 @@
 cmake^
   -DBOOST_ROOT=C:\Libraries\boost_1_69_0^
   -DBOOST_LIBRARYDIR=C:\Libraries\boost_1_69_0\lib64-msvc-14.1^
+  -DFLEX_HOME=C:\Adobe\Flex\SDK\4.6^
   -DLIBEVENT_ROOT=C:\Libraries\libevent-2.1.8^
   -DZLIB_ROOT=C:\Libraries\zlib-1.2.11^
   -DCMAKE_BUILD_TYPE=Release^
@@ -41,4 +42,4 @@
 cmake --build . --target check || EXIT /B
 
 :: Install
-cmake --build . --target install
\ No newline at end of file
+cmake --build . --target install