diff --git a/include/boost/unordered/detail/foa.hpp b/include/boost/unordered/detail/foa.hpp
index 0d48c911..89d79dae 100644
--- a/include/boost/unordered/detail/foa.hpp
+++ b/include/boost/unordered/detail/foa.hpp
@@ -261,12 +261,20 @@ private:
       0xF8F8F8F8u,0xF9F9F9F9u,0xFAFAFAFAu,0xFBFBFBFBu,0xFCFCFCFCu,0xFDFDFDFDu,0xFEFEFEFEu,0xFFFFFFFFu,
     };
 
+#if defined(__MSVC_RUNTIME_CHECKS)
+    return (int)word[hash&0xffu];
+#else
     return (int)word[(unsigned char)hash];
+#endif
   }
 
   inline static unsigned char reduced_hash(std::size_t hash)
   {
+#if defined(__MSVC_RUNTIME_CHECKS)
+    return match_word(hash)&0xffu;
+#else
     return (unsigned char)match_word(hash);
+#endif
   }
 
   inline unsigned char& at(std::size_t pos)
@@ -517,7 +525,11 @@ struct group15
     std::size_t     pos=reinterpret_cast<uintptr_t>(pc)%sizeof(group15);
     group15        *pg=reinterpret_cast<group15*>(pc-pos);
     boost::uint64_t x=((pg->m[0])>>pos)&0x000100010001ull;
+#if defined(__MSVC_RUNTIME_CHECKS)
+    boost::uint32_t y=(x|(x>>15)|(x>>30))&0xffffffffu;
+#else
     boost::uint32_t y=static_cast<boost::uint32_t>(x|(x>>15)|(x>>30));
+#endif
     return !pg->is_not_overflowed(y);
   };
 
@@ -532,7 +544,11 @@ struct group15
   inline int match_occupied()const
   {
     boost::uint64_t x=m[0]|m[1];
+#if defined(__MSVC_RUNTIME_CHECKS)
+    boost::uint32_t y=(x|(x>>32))&0xffffffffu;
+#else
     boost::uint32_t y=static_cast<boost::uint32_t>(x|(x>>32));
+#endif
     y|=y>>16;
     return y&0x7FFF;
   }
@@ -567,7 +583,11 @@ private:
       240,241,242,243,244,245,246,247,248,249,250,251,252,253,254,255,
     };
     
+#if defined(__MSVC_RUNTIME_CHECKS)
+  return table[hash&0xffu];
+#else
     return table[(unsigned char)hash];
+#endif
   }
 
   inline void set_impl(std::size_t pos,std::size_t n)
@@ -994,6 +1014,7 @@ void swap_if(T&,T&){}
 
 inline void prefetch(const void* p)
 {
+  (void) p;
 #if defined(BOOST_GCC)||defined(BOOST_CLANG)
   __builtin_prefetch((const char*)p);
 #elif defined(BOOST_UNORDERED_SSE2)
diff --git a/include/boost/unordered/detail/prime_fmod.hpp b/include/boost/unordered/detail/prime_fmod.hpp
index 885c071b..4c538487 100644
--- a/include/boost/unordered/detail/prime_fmod.hpp
+++ b/include/boost/unordered/detail/prime_fmod.hpp
@@ -117,9 +117,15 @@ namespace boost {
 #if defined(BOOST_UNORDERED_FCA_HAS_64B_SIZE_T)
           std::size_t sizes_under_32bit = inv_sizes32_len;
           if (BOOST_LIKELY(size_index < sizes_under_32bit)) {
+#if defined(__MSVC_RUNTIME_CHECKS)
+            return fast_modulo(
+              boost::uint32_t(hash & 0xffffffffu) + boost::uint32_t(hash >> 32),
+              inv_sizes32[size_index], boost::uint32_t(sizes[size_index]));
+#else
             return fast_modulo(
               boost::uint32_t(hash) + boost::uint32_t(hash >> 32),
               inv_sizes32[size_index], boost::uint32_t(sizes[size_index]));
+#endif
           } else {
             return positions[size_index - sizes_under_32bit](hash);
           }
diff --git a/test/unordered/prime_fmod_tests.cpp b/test/unordered/prime_fmod_tests.cpp
index ba0f92d4..2094bc57 100644
--- a/test/unordered/prime_fmod_tests.cpp
+++ b/test/unordered/prime_fmod_tests.cpp
@@ -21,8 +21,7 @@ void macros_test()
     BOOST_ERROR("std::numeric_limits<size_t>::digits >= 64, but "
                 "BOOST_UNORDERED_FCA_HAS_64B_SIZE_T is not defined");
 #endif
-  }
-  else {
+  } else {
 #if defined(BOOST_UNORDERED_FCA_HAS_64B_SIZE_T)
     BOOST_ERROR("std::numeric_limits<size_t>::digits < 64, but "
                 "BOOST_UNORDERED_FCA_HAS_64B_SIZE_T is defined");
@@ -155,7 +154,7 @@ void get_remainder_test()
 
   for (std::size_t i = 0; i < 1000000u; ++i) {
     boost::uint64_t f = rng();
-    boost::uint32_t d = static_cast<uint32_t>(rng());
+    boost::uint32_t d = rng() & 0xffffffffu;
 
     boost::uint64_t r1 =
       boost::unordered::detail::prime_fmod_size<>::get_remainder(f, d);
@@ -180,14 +179,14 @@ void modulo_test()
   boost::detail::splitmix64 rng;
 
   for (std::size_t i = 0; i < 1000000u; ++i) {
-    std::size_t hash = static_cast<std::size_t>(rng());
+    std::size_t hash = static_cast<std::size_t>(-1) & rng();
 
     for (std::size_t j = 0; j < sizes_len; ++j) {
       std::size_t h = hash;
 
 #if defined(BOOST_UNORDERED_FCA_HAS_64B_SIZE_T)
       if (sizes[j] <= UINT_MAX) {
-        h = boost::uint32_t(h) + boost::uint32_t(h >> 32);
+        h = boost::uint32_t(h & 0xffffffffu) + boost::uint32_t(h >> 32);
       }
 #endif
       std::size_t p1 =