diff --git a/src/lisp/x86-arch.c b/src/lisp/x86-arch.c
index c694ceae943f13a3ac15570dac88c443f66b2e96..841e2ccbad8fba29c9ab9678e012a00f1dcecf5f 100644
--- a/src/lisp/x86-arch.c
+++ b/src/lisp/x86-arch.c
@@ -108,17 +108,16 @@ arch_init(fpu_mode_t mode)
 
     have_sse2 = arch_support_sse2() && os_support_sse2();
     
+    if (!have_sse2) {
+        fprintf(stderr, "CMUCL requires a SSE2 support; exiting\n");
+        abort();
+    }
+        
     switch (mode) {
       case AUTO:
-          if (have_sse2) {
-              return "lisp-sse2.core";
-          } else {
-              return "lisp-x87.core";
-          }
-          break;
       case X87:
-          return "lisp-x87.core";
-          break;
+          fprintf(stderr, "fpu mode AUTO or X87 is not longer supported.\n");
+          /* Fall through and return the sse2 core */
       case SSE2:
           return "lisp-sse2.core";
           break;