diff --git a/Source/msg.cpp b/Source/msg.cpp
index 887557432..e8ff1ec1a 100644
--- a/Source/msg.cpp
+++ b/Source/msg.cpp
@@ -770,7 +770,7 @@ void DeltaImportData(_cmd_id cmd, uint32_t recvOffset, int pnum)
 
 #ifdef USE_PKWARE
 	if (sgRecvBuf[0] != std::byte { 0 }) {
-		deltaSize = PkwareDecompress(&sgRecvBuf[1], deltaSize, sizeof(sgRecvBuf) - 1);
+		deltaSize = PkwareDecompress(&sgRecvBuf[1], static_cast<uint32_t>(deltaSize), sizeof(sgRecvBuf) - 1);
 		if (deltaSize == 0) {
 			Log("PKWare decompression failure, dropping player {}", pnum);
 			SNetDropPlayer(pnum, LEAVE_DROP);
@@ -3303,7 +3303,7 @@ bool ValidateCmdSize(size_t requiredCmdSize, size_t maxCmdSize, size_t playerId)
 		return true;
 
 	Log("Suspiciously small packet size, dropping player {}", playerId);
-	SNetDropPlayer(playerId, LEAVE_DROP);
+	SNetDropPlayer(static_cast<uint8_t>(playerId), LEAVE_DROP);
 	return false;
 }
 
diff --git a/test/text_render_integration_test.cpp b/test/text_render_integration_test.cpp
index 6826834a7..06f8857e5 100644
--- a/test/text_render_integration_test.cpp
+++ b/test/text_render_integration_test.cpp
@@ -226,7 +226,7 @@ std::vector<std::byte> ReadFile(const std::string &path)
 	SDL_RWops *rwops = SDL_RWFromFile(path.c_str(), "rb");
 	std::vector<std::byte> result;
 	if (rwops == nullptr) return result;
-	const size_t size = SDL_RWsize(rwops);
+	const size_t size = static_cast<size_t>(SDL_RWsize(rwops));
 	result.resize(size);
 	SDL_RWread(rwops, result.data(), size, 1);
 	SDL_RWclose(rwops);
diff --git a/test/vision_test.cpp b/test/vision_test.cpp
index 8a6372e05..02a5f830b 100644
--- a/test/vision_test.cpp
+++ b/test/vision_test.cpp
@@ -86,7 +86,11 @@ void dumpVisibleEnv()
 		}
 		sz += snprintf(buf + sz, sizeof(buf) - sz, "\n");
 	}
+#ifdef _WIN32
+	_write(2, buf, sz);
+#else
 	write(2, buf, sz);
+#endif
 }
 
 // This test case checks the visibility of surrounding objects