diff --git a/CMakeLists.txt b/CMakeLists.txt
index 38f963a60e8..4ab7485e59b 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -621,6 +621,12 @@ if(FLB_TLS)
   if(OPENSSL_FOUND)
     FLB_DEFINITION(FLB_HAVE_OPENSSL)
   endif()
+
+  if (FLB_SYSTEM_WINDOWS AND NOT(OPENSSL_FOUND))
+    # win32 builds w/o openssl will fail later so we might as well catch it
+    # early instead.
+    MESSAGE(FATAL_ERROR "OpenSSL required on Windows, see DEVELOPER_GUIDE.md")
+  endif()
 endif()
 
 # Metrics
diff --git a/cmake/windows-setup.cmake b/cmake/windows-setup.cmake
index fa67cb0d872..4f57880a48b 100644
--- a/cmake/windows-setup.cmake
+++ b/cmake/windows-setup.cmake
@@ -119,9 +119,10 @@ find_package(FLEX)
 find_package(BISON)
 
 if (NOT (${FLEX_FOUND} AND ${BISON_FOUND}))
-  message(STATUS "flex and bison not found. Disable stream_processor building.")
-  set(FLB_STREAM_PROCESSOR No)
-  set(FLB_RECORD_ACCESSOR  No)
+  # The build will fail later if flex and bison are missing, so there's no
+  # point attempting to continue. There's no test cover for windows builds
+  # without FLB_PARSER anyway.
+  message(FATAL_ERROR "flex and bison not found, see DEVELOPER_GUIDE.md")
 endif()
 
 if (MSVC)