diff --git a/msix/ubuntu-pro-agent-launcher/console.cpp b/msix/ubuntu-pro-agent-launcher/console.cpp
index a573a03e6..6c8287e2b 100644
--- a/msix/ubuntu-pro-agent-launcher/console.cpp
+++ b/msix/ubuntu-pro-agent-launcher/console.cpp
@@ -90,7 +90,7 @@ Process PseudoConsole::StartProcess(std::wstring commandLine) {
   si.StartupInfo.dwFlags = STARTF_USESTDHANDLES;
   si.lpAttributeList = attributes.get();
 
-  Process p{0};
+  Process p{};
   if (!CreateProcessW(NULL, commandLine.data(), NULL, NULL, FALSE,
                       EXTENDED_STARTUPINFO_PRESENT, NULL, NULL, &si.StartupInfo,
                       &p)) {
@@ -133,7 +133,7 @@ int EventLoop::Run() {
       DispatchMessage(&msg);
     } else {
       // invoke the listener subscribed to the handle that was signaled.
-      if (auto done = listeners_[signaledIndex](handles_[signaledIndex]);
+      if (auto done = listeners_.at(signaledIndex)(handles_.at(signaledIndex));
           done.has_value()) {
         return done.value();
       }
diff --git a/msix/ubuntu-pro-agent-launcher/console.hpp b/msix/ubuntu-pro-agent-launcher/console.hpp
index 8af931d17..36ee0f457 100644
--- a/msix/ubuntu-pro-agent-launcher/console.hpp
+++ b/msix/ubuntu-pro-agent-launcher/console.hpp
@@ -5,13 +5,32 @@
 #include <initializer_list>
 #include <optional>
 #include <string>
+#include <type_traits>
 #include <utility>
+#include <vector>
 
 namespace up4w {
 // An RAII wrapper around the PROCESS_INFORMATION structure to ease preventing
 // HANDLE leaks.
 struct Process : PROCESS_INFORMATION {
-  ~Process() {
+  Process(Process const& other) = delete;
+  Process& operator=(Process const& other) = delete;
+  Process(Process&& other) noexcept { *this = std::move(other); }
+  Process& operator=(Process&& other) noexcept {
+    hProcess = std::exchange(other.hProcess, nullptr);
+    hThread = std::exchange(other.hThread, nullptr);
+    dwProcessId = std::exchange(other.dwProcessId, 0);
+    dwThreadId = std::exchange(other.dwThreadId, 0);
+    return *this;
+  }
+  Process() noexcept {
+    hProcess = nullptr;
+    hThread = nullptr;
+    dwProcessId = 0;
+    dwThreadId = 0;
+  }
+
+  ~Process() noexcept {
     if (hThread != nullptr && hThread != INVALID_HANDLE_VALUE) {
       CloseHandle(hThread);
     }
diff --git a/msix/ubuntu-pro-agent-launcher/error.cpp b/msix/ubuntu-pro-agent-launcher/error.cpp
index c040ecc94..fcc312c60 100644
--- a/msix/ubuntu-pro-agent-launcher/error.cpp
+++ b/msix/ubuntu-pro-agent-launcher/error.cpp
@@ -3,8 +3,8 @@
 #include <fstream>
 
 namespace up4w {
-std::wstring MakePathRelativeToEnvDir(std::wstring_view destination,
-                                      std::wstring_view envDir) {
+std::wstring UnderLocalAppDataPath(std::wstring_view destination) {
+  std::wstring_view localAppData = L"LOCALAPPDATA";
   std::wstring resultPath{};
   resultPath.resize(MAX_PATH);
 
@@ -12,11 +12,15 @@ std::wstring MakePathRelativeToEnvDir(std::wstring_view destination,
       static_cast<DWORD>(resultPath.capacity() - destination.size() - 1);
 
   auto length =
-      GetEnvironmentVariable(envDir.data(), resultPath.data(), truncatedLength);
+      GetEnvironmentVariable(localAppData.data(), resultPath.data(), truncatedLength);
   if (length == 0) {
     return {};
   }
 
+  if (length > truncatedLength) {
+    throw hresult_exception{CO_E_PATHTOOLONG};
+  }
+
   resultPath.insert(length, destination.data());
   return resultPath;
 }
@@ -26,7 +30,7 @@ void LogSingleShot(std::filesystem::path const& logFilePath,
   auto const time =
       std::chrono::current_zone()->to_local(std::chrono::system_clock::now());
 
-  std::ofstream logfile{logFilePath};
+  std::ofstream logfile{logFilePath, std::ios::app};
   logfile << std::format("{:%Y-%m-%d %T}: {}\n", time, message);
 }
 
diff --git a/msix/ubuntu-pro-agent-launcher/error.hpp b/msix/ubuntu-pro-agent-launcher/error.hpp
index 0693b3d0a..a818ec93f 100644
--- a/msix/ubuntu-pro-agent-launcher/error.hpp
+++ b/msix/ubuntu-pro-agent-launcher/error.hpp
@@ -54,10 +54,9 @@ class hresult_exception {
 };
 
 /// Computes the absolute path resulting of joining the [destination] into the
-/// value of the environment variable [envDir]. Returns empty string if the
+/// value of the environment variable [LOCALAPPDATA]. Returns empty string if the
 /// environment variable is undefined.
-std::wstring MakePathRelativeToEnvDir(std::wstring_view destination,
-                                      std::wstring_view envDir);
+std::wstring UnderLocalAppDataPath(std::wstring_view destination);
 
 // Opens the log file, writes the message with a timestamp and closes it.
 void LogSingleShot(std::filesystem::path const& logFilePath,
diff --git a/msix/ubuntu-pro-agent-launcher/main.cpp b/msix/ubuntu-pro-agent-launcher/main.cpp
index 29974d345..884dd870c 100644
--- a/msix/ubuntu-pro-agent-launcher/main.cpp
+++ b/msix/ubuntu-pro-agent-launcher/main.cpp
@@ -12,9 +12,8 @@
 #include "error.hpp"
 
 std::filesystem::path const& logPath() {
-  static std::filesystem::path localAppDataPath =
-      up4w::MakePathRelativeToEnvDir(
-          L"\\Ubuntu Pro\\ubuntu-pro-agent-launcher.log", L"LOCALAPPDATA");
+  static std::filesystem::path localAppDataPath = up4w::UnderLocalAppDataPath(
+      L"\\Ubuntu Pro\\ubuntu-pro-agent-launcher.log");
   return localAppDataPath;
 }
 
@@ -80,4 +79,12 @@ int WINAPI wWinMain(HINSTANCE, HINSTANCE, PWSTR pCmdLine, int) try {
 
   up4w::LogSingleShot(localAppDataPath, err.what());
   return 3;
+} catch (...) {
+  std::filesystem::path const& localAppDataPath = logPath();
+  if (localAppDataPath.empty()) {
+    return 1;
+  }
+
+  up4w::LogSingleShot(localAppDataPath, "An unknown exception was thrown.\n");
+  return 4;
 }