diff --git a/lib/util/CompilerCompatible.h b/lib/util/CompilerCompatible.h
new file mode 100644
index 00000000..405b4c07
--- /dev/null
+++ b/lib/util/CompilerCompatible.h
@@ -0,0 +1,55 @@
+#pragma once 
+
+
+#define COMPILER_FATAL     
+#define COMPILER_GCC_WARN  "Compiler" COMPILER_STRING " is known to not work with Grid under -O3 due to compiler bugs"
+
+#if defined(__clang__)
+
+  #if __clang_major < 3
+    #error "This clang++ version is known to not work with Grid due to compiler bugs"
+  #endif
+
+  #if __clang_major == 3
+    #if __clang_minor < 5
+    #error "This clang++ version is known to not work with Grid due to compiler bugs"
+    #endif
+  #endif 
+
+#endif
+
+// Intel compiler *ALSO* has __GNUC__ defined so must if/else GCC checks
+#ifdef __INTEL_COMPILER
+
+#if __INTEL_COMPILER < 1600
+  #error "This icpc version is known to not work with Grid due to compiler bugs"
+#endif
+
+#else 
+
+  #if defined(__GNUC__)
+
+    #if __GNUC__ < 4 
+      #error "g++ prior to version 4 is known to not work with Grid due to compiler bugs"
+    #endif
+
+    #if __GNUC__ == 4 
+      #if __GNUC_MINOR__ != 9 
+      #error "g++ 4.9 is the only gcc-4.x version known to work with Grid due to compiler bugs"
+      #endif
+    #endif
+
+    #if __GNUC__ == 5
+      #warning "g++ version 5 is known to not work with Grid due to compiler bugs under -O3 : ensure you run make check"
+    #endif
+
+    #if __GNUC__ == 6
+      #if __GNUC_MINOR__ < 3
+        #warning "This g++6.3 is the first recent g++ version known to work with Grid: ensure you run make check"
+      #endif
+    #endif
+
+  #endif
+
+#endif
+
diff --git a/lib/util/Init.cc b/lib/util/Init.cc
index e228dd77..fe3b1734 100644
--- a/lib/util/Init.cc
+++ b/lib/util/Init.cc
@@ -48,6 +48,8 @@ Author: paboyle <paboyle@ph.ed.ac.uk>
 
 #include <Grid/Grid.h>
 
+#include <Grid/util/CompilerCompatible.h>
+
 
 #include <fenv.h>
 #ifdef __APPLE__