diff --git a/rts/Stable.c b/rts/Stable.c
index 046fb3be4277b40a867e9da8969bc79e83c28dd9..a2c47d785c64cd1d48c055a2e86d3af2e728edb4 100644
--- a/rts/Stable.c
+++ b/rts/Stable.c
@@ -218,6 +218,9 @@ lookupStableName_(StgPtr p)
    */
   p = (StgPtr)removeIndirections((StgClosure*)p);
 
+  // register the untagged pointer.  This just makes things simpler.
+  p = (StgPtr)UNTAG_CLOSURE((StgClosure*)p);
+
   sn_tmp = lookupHashTable(addrToStableHash,(W_)p);
   sn = (StgWord)sn_tmp;