diff --git a/src/s3plugin.cpp b/src/s3plugin.cpp
index 4cd63f4..368b323 100644
--- a/src/s3plugin.cpp
+++ b/src/s3plugin.cpp
@@ -1225,8 +1225,8 @@ UploadOutcome InitiateAppend(Writer& writer, size_t source_bytes_to_copy)
 	int64_t start_range = 0;
 	while (source_bytes_to_copy > Writer::buff_min_)
 	{
-		const size_t copy_count =
-		    source_bytes_to_copy > Writer::buff_max_ ? Writer::buff_max_ : source_bytes_to_copy;
+		const int64_t copy_count =
+		    source_bytes_to_copy > Writer::buff_max_ ? Writer::buff_max_ : static_cast<int64_t>(source_bytes_to_copy);
 			
 		// peculiarity of AWS: the range for the copy request has an inclusive end,
 		// meaning that the bytes numbered start_range to end_range included are copied
diff --git a/test/drivertest.cpp b/test/drivertest.cpp
index 3858e6a..32b0320 100644
--- a/test/drivertest.cpp
+++ b/test/drivertest.cpp
@@ -126,8 +126,11 @@ int launch_test(const char *inputFilename, int nBufferSize) {
                  << boost::uuids::random_generator()() << "/output.txt";
   std::stringstream localOutput;
 #ifdef _WIN32
-  localOutput << std::getenv("TEMP") << "\\out-"
-              << boost::uuids::random_generator()() << ".txt";
+  size_t len;
+  char tempValue[2048];
+  getenv_s(&len, tempValue, 2048, "TEMP");
+  localOutput << tempValue << "\\out-" << boost::uuids::random_generator()()
+              << ".txt";
 #else
   localOutput << "/tmp/out-" << boost::uuids::random_generator()() << ".txt";
 #endif
@@ -334,9 +337,9 @@ int copyFileWithFseek(const char *file_name_input, const char *file_name_output,
     // Reads the file by steps of nBufferSize and writes to the output file at
     // each step
     char *buffer = new char[nBufferSize + 1]();
-    long long int sizeRead = nBufferSize;
-    long long int sizeWrite;
-    int cummulativeRead = 0;
+    long long sizeRead = nBufferSize;
+    long long sizeWrite;
+    long long cummulativeRead = 0;
     driver_fseek(fileinput, 0, SEEK_SET);
     while (sizeRead == nBufferSize && copy_status == kSuccess) {
       driver_fseek(fileinput, cummulativeRead, SEEK_SET);