diff --git a/tests/UnitTests/subprocess1.cpp b/tests/UnitTests/subprocess1.cpp
index 1ed619b93..e8db524a1 100644
--- a/tests/UnitTests/subprocess1.cpp
+++ b/tests/UnitTests/subprocess1.cpp
@@ -9,14 +9,16 @@
 int main(int argc, char* argv[])
 {
 	{
-		Nz::File file(Nz::Utf8Path("step1_success.txt"), Nz::OpenMode::Write);
+		Nz::File file(Nz::Utf8Path("step1_success.txt"), Nz::OpenMode::Write | Nz::OpenMode::Unbuffered);
 		file.Write("1");
+		file.Flush();
 	}
 
 	for (int i = 1; i < argc; ++i)
 	{
-		Nz::File file(Nz::Utf8Path(Nz::Format("step2_param{}.txt", i)), Nz::OpenMode::Write);
+		Nz::File file(Nz::Utf8Path(Nz::Format("step2_param{}.txt", i)), Nz::OpenMode::Write | Nz::OpenMode::Unbuffered);
 		file.Write(argv[i]);
+		file.Flush();
 	}
 
 	std::vector<std::string> parameters;
@@ -25,13 +27,15 @@ int main(int argc, char* argv[])
 	Nz::Result result = Nz::Process::SpawnDetached("../UnitTests_sub2", parameters);
 	if (result)
 	{
-		Nz::File file(Nz::Utf8Path("step3_pid.txt"), Nz::OpenMode::Write);
+		Nz::File file(Nz::Utf8Path("step3_pid.txt"), Nz::OpenMode::Write | Nz::OpenMode::Unbuffered);
 		file.Write(std::to_string(result.GetValue()));
+		file.Flush();
 	}
 	else
 	{
-		Nz::File file(Nz::Utf8Path("step3_failure.txt"), Nz::OpenMode::Write);
-		file.Write(result.GetError());
+		Nz::File errFile(Nz::Utf8Path("step3_failure.txt"), Nz::OpenMode::Write | Nz::OpenMode::Unbuffered);
+		errFile.Write(result.GetError());
+		errFile.Flush();
 	}
 
 	// Wait for our child process to start and check for our existence
diff --git a/tests/UnitTests/subprocess2.cpp b/tests/UnitTests/subprocess2.cpp
index 808580346..c823f878e 100644
--- a/tests/UnitTests/subprocess2.cpp
+++ b/tests/UnitTests/subprocess2.cpp
@@ -12,8 +12,9 @@ int main(int argc, char* argv[])
 {
 	if (argc != 2)
 	{
-		Nz::File errFile(Nz::Utf8Path("step4_failure.txt"), Nz::OpenMode::Write);
+		Nz::File errFile(Nz::Utf8Path("step4_failure.txt"), Nz::OpenMode::Write | Nz::OpenMode::Unbuffered);
 		errFile.Write(Nz::Format("unexpected argc: {}", argc));
+		errFile.Flush();
 
 		return EXIT_FAILURE;
 	}
@@ -21,34 +22,39 @@ int main(int argc, char* argv[])
 	Nz::Pid pid;
 	if (auto pidParse = std::from_chars(argv[1], argv[1] + std::strlen(argv[1]), pid); pidParse.ec != std::errc())
 	{
-		Nz::File errFile(Nz::Utf8Path("step4_failure.txt"), Nz::OpenMode::Write);
+		Nz::File errFile(Nz::Utf8Path("step4_failure.txt"), Nz::OpenMode::Write | Nz::OpenMode::Unbuffered);
 		errFile.Write(Nz::Format("invalid pid: {}", argv[1]));
+		errFile.Flush();
 
 		return EXIT_FAILURE;
 	}
 
-	Nz::File successFile4(Nz::Utf8Path("step4_success.txt"), Nz::OpenMode::Write);
+	Nz::File successFile4(Nz::Utf8Path("step4_success.txt"), Nz::OpenMode::Write | Nz::OpenMode::Unbuffered);
 	successFile4.Write("1");
+	successFile4.Flush();
 
 	Nz::Result result = Nz::Process::Exists(pid);
 	if (!result)
 	{
-		Nz::File errFile(Nz::Utf8Path("step5_failure.txt"), Nz::OpenMode::Write);
+		Nz::File errFile(Nz::Utf8Path("step5_failure.txt"), Nz::OpenMode::Write | Nz::OpenMode::Unbuffered);
 		errFile.Write(Nz::Format("failed to retrieve parent process status: {}", result.GetError()));
+		errFile.Flush();
 
 		return EXIT_FAILURE;
 	}
 
 	if (!result.GetValue())
 	{
-		Nz::File file(Nz::Utf8Path("step5_failure.txt"), Nz::OpenMode::Write);
-		file.Write("parent process is already dead");
+		Nz::File errFile(Nz::Utf8Path("step5_failure.txt"), Nz::OpenMode::Write | Nz::OpenMode::Unbuffered);
+		errFile.Write("parent process is already dead");
+		errFile.Flush();
 
 		return EXIT_FAILURE;
 	}
 
-	Nz::File successFile5(Nz::Utf8Path("step5_success.txt"), Nz::OpenMode::Write);
+	Nz::File successFile5(Nz::Utf8Path("step5_success.txt"), Nz::OpenMode::Write | Nz::OpenMode::Unbuffered);
 	successFile5.Write("1");
+	successFile5.Flush();
 
 	// Wait until parent dies
 	std::this_thread::sleep_for(std::chrono::milliseconds(500));
@@ -56,22 +62,25 @@ int main(int argc, char* argv[])
 	result = Nz::Process::Exists(pid);
 	if (!result)
 	{
-		Nz::File errFile(Nz::Utf8Path("step6_failure.txt"), Nz::OpenMode::Write);
+		Nz::File errFile(Nz::Utf8Path("step6_failure.txt"), Nz::OpenMode::Write | Nz::OpenMode::Unbuffered);
 		errFile.Write(Nz::Format("failed to retrieve parent process status after waiting: {}", result.GetError()));
+		errFile.Flush();
 
 		return EXIT_FAILURE;
 	}
 
 	if (result.GetValue())
 	{
-		Nz::File errFile(Nz::Utf8Path("step6_failure.txt"), Nz::OpenMode::Write);
+		Nz::File errFile(Nz::Utf8Path("step6_failure.txt"), Nz::OpenMode::Write | Nz::OpenMode::Unbuffered);
 		errFile.Write("parent process is still alive");
+		errFile.Flush();
 
 		return EXIT_FAILURE;
 	}
 
-	Nz::File successFile6(Nz::Utf8Path("step6_success.txt"), Nz::OpenMode::Write);
+	Nz::File successFile6(Nz::Utf8Path("step6_success.txt"), Nz::OpenMode::Write | Nz::OpenMode::Unbuffered);
 	successFile6.Write("1");
+	successFile6.Flush();
 
 	// Wait for the unit tests process to check our existence
 	std::this_thread::sleep_for(std::chrono::milliseconds(3000));