diff --git a/src/connection_win.cpp b/src/connection_win.cpp
index 9cc77e5..b750f05 100644
--- a/src/connection_win.cpp
+++ b/src/connection_win.cpp
@@ -72,7 +72,7 @@ bool BaseConnection::Close()
 bool BaseConnection::Write(const void* data, size_t length)
 {
     auto self = reinterpret_cast<BaseConnectionWin*>(this);
-    return ::WriteFile(self->pipe, data, length, nullptr, nullptr) == TRUE;
+    return ::WriteFile(self->pipe, data, (DWORD)length, nullptr, nullptr) == TRUE;
 }
 
 bool BaseConnection::Read(void* data, size_t length)
@@ -81,7 +81,7 @@ bool BaseConnection::Read(void* data, size_t length)
     DWORD bytesAvailable = 0;
     if (::PeekNamedPipe(self->pipe, nullptr, 0, nullptr, &bytesAvailable, nullptr)) {
         if (bytesAvailable >= length) {
-            if (::ReadFile(self->pipe, data, length, nullptr, nullptr) == TRUE) {
+            if (::ReadFile(self->pipe, data, (DWORD)length, nullptr, nullptr) == TRUE) {
                 return true;
             }
             else {
diff --git a/src/rpc_connection.cpp b/src/rpc_connection.cpp
index a8d6e9f..46d8da3 100644
--- a/src/rpc_connection.cpp
+++ b/src/rpc_connection.cpp
@@ -48,8 +48,8 @@ void RpcConnection::Open()
     }
     else {
         sendFrame.opcode = Opcode::Handshake;
-        sendFrame.length =
-          JsonWriteHandshakeObj(sendFrame.message, sizeof(sendFrame.message), RpcVersion, appId);
+        sendFrame.length = (uint32_t)JsonWriteHandshakeObj(
+          sendFrame.message, sizeof(sendFrame.message), RpcVersion, appId);
 
         if (connection->Write(&sendFrame, sizeof(MessageFrameHeader) + sendFrame.length)) {
             state = State::SentHandshake;
@@ -73,7 +73,7 @@ bool RpcConnection::Write(const void* data, size_t length)
 {
     sendFrame.opcode = Opcode::Frame;
     memcpy(sendFrame.message, data, length);
-    sendFrame.length = length;
+    sendFrame.length = (uint32_t)length;
     if (!connection->Write(&sendFrame, sizeof(MessageFrameHeader) + length)) {
         Close();
         return false;