diff --git a/src/learner/evaluation-inl.hpp b/src/learner/evaluation-inl.hpp
index d5cb9fc36..0b73ec1e1 100644
--- a/src/learner/evaluation-inl.hpp
+++ b/src/learner/evaluation-inl.hpp
@@ -123,7 +123,7 @@ struct EvalAMS : public IEvaluator {
     const double br = 10.0;
     unsigned thresindex = 0;
     double s_tp = 0.0, b_fp = 0.0, tams = 0.0;
-    for (unsigned i = 0; i < ndata-1 && i < ntop; ++i) {
+    for (unsigned i = 0; i < static_cast<unsigned>(ndata-1) && i < ntop; ++i) {
       const unsigned ridx = rec[i].second;
       const float wt = info.weights[ridx];
       if (info.labels[ridx] > 0.5f) {
diff --git a/src/learner/objective-inl.hpp b/src/learner/objective-inl.hpp
index 02c896274..0e6b5ec7d 100644
--- a/src/learner/objective-inl.hpp
+++ b/src/learner/objective-inl.hpp
@@ -169,7 +169,7 @@ class SoftmaxMultiClassObj : public IObjFunction {
     std::vector<bst_gpair> &gpair = *out_gpair;
     gpair.resize(preds.size());
     const unsigned nstep = static_cast<unsigned>(info.labels.size() * nclass);
-    const unsigned ndata = static_cast<bst_omp_uint>(preds.size() / nclass);
+    const bst_omp_uint ndata = static_cast<bst_omp_uint>(preds.size() / nclass);
     #pragma omp parallel
     {
       std::vector<float> rec(nclass);
diff --git a/windows/xgboost/xgboost.vcxproj b/windows/xgboost/xgboost.vcxproj
index 064dd6ee6..8b88dbf2e 100644
--- a/windows/xgboost/xgboost.vcxproj
+++ b/windows/xgboost/xgboost.vcxproj
@@ -99,6 +99,7 @@
       <Optimization>MaxSpeed</Optimization>
       <FunctionLevelLinking>true</FunctionLevelLinking>
       <IntrinsicFunctions>true</IntrinsicFunctions>
+      <OpenMPSupport>true</OpenMPSupport>
     </ClCompile>
     <Link>
       <GenerateDebugInformation>true</GenerateDebugInformation>