diff --git a/HMCLauncher/HMCL/main.cpp b/HMCLauncher/HMCL/main.cpp
index d2a324fa6..1e6869ecd 100644
--- a/HMCLauncher/HMCL/main.cpp
+++ b/HMCLauncher/HMCL/main.cpp
@@ -129,11 +129,8 @@ int APIENTRY wWinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
       DWORD dataSize = SizeofResource(NULL, scriptFileResource);
       void *data = LockResource(scriptHandle);
 
-      std::wstring tempPath;
-      if (ERROR_SUCCESS != MyGetTempPath(tempPath)) goto error;
-
       std::wstring tempScriptPath;
-      if (ERROR_SUCCESS != MyGetTempFileName(tempPath, L"hmcl", tempScriptPath)) goto error;
+      if (ERROR_SUCCESS != MyGetTempFile(L"hmcl-download-java-", L"ps1", tempScriptPath)) goto error;
 
       HANDLE hFile;
       DWORD dwBytesWritten = 0;
@@ -149,12 +146,20 @@ int APIENTRY wWinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
 
       std::wstring commandLineBuffer;
 
-      commandLineBuffer += L"powershell.exe -ExecutionPolicy Bypass ";
+      commandLineBuffer += L"powershell.exe -WindowStyle Hidden -ExecutionPolicy Bypass -File ";
       MyAppendPathToCommandLine(commandLineBuffer, tempScriptPath);
       commandLineBuffer += L" -JavaDir ";
       MyAppendPathToCommandLine(commandLineBuffer, hmclJavaDir);
 
-      MyCreateProcess(commandLineBuffer, workdir);
+      STARTUPINFO si;
+      PROCESS_INFORMATION pi;
+      si.cb = sizeof(si);
+      ZeroMemory(&si, sizeof(si));
+      ZeroMemory(&pi, sizeof(pi));
+      if (!CreateProcess(NULL, &commandLineBuffer[0], NULL, NULL, false, NORMAL_PRIORITY_CLASS, NULL, NULL, &si, &pi)) goto error;
+      WaitForSingleObject(pi.hProcess, INFINITE);
+      DeleteFile(tempScriptPath.c_str());
+
       // Try starting again after installing Java
       FindJavaInDirAndLaunchJVM(hmclJavaDir, workdir, exeName);
     }
diff --git a/HMCLauncher/HMCL/os.cpp b/HMCLauncher/HMCL/os.cpp
index 8718bd18e..24a619c6d 100644
--- a/HMCLauncher/HMCL/os.cpp
+++ b/HMCLauncher/HMCL/os.cpp
@@ -125,34 +125,38 @@ void MyPathAddBackslash(std::wstring &filePath) {
   }
 }
 
-LSTATUS MyGetTempPath(std::wstring &out) {
-  out = std::wstring();
+LSTATUS MyGetTempFile(const std::wstring &prefixString, const std::wstring &ext, std::wstring &out) {
   out.resize(MAX_PATH);
-
   DWORD res = GetTempPath(MAX_PATH, &out[0]);
   if (res == 0) {
     return GetLastError();
   }
+
   out.resize(res);
-  return ERROR_SUCCESS;
-}
 
-LSTATUS MyGetTempFileName(const std::wstring &pathName, const std::wstring &prefixString, std::wstring &out) {
-  out = std::wstring();
-  out.resize(MAX_PATH);
+  GUID guid;
+  CoCreateGuid(&guid);
 
-  if (GetTempFileName(pathName.c_str(), prefixString.c_str(), 0, &out[0]) == 0) {
-    out.resize(0);
-    return GetLastError();
+  WCHAR buffer[MAX_PATH];
+  int n = StringFromGUID2(guid, buffer, MAX_PATH);
+  if (n == 0) {
+      return CO_E_PATHTOOLONG;
   }
-  out.resize(wcslen(&out[0]));
+
+  MyPathAddBackslash(out);
+  out += prefixString;
+  out += buffer;
+  out += L'.';
+  out += ext;
+
   return ERROR_SUCCESS;
 }
 
 void MyAppendPathToCommandLine(std::wstring &commandLine, const std::wstring &path) {
   commandLine += L'"';
-  for (WCHAR ch : path) {
-    if (ch == L'\\') {
+  for (size_t i = 0; i < path.size(); i++) {
+    WCHAR ch = path[i];
+    if (ch == L'\\' && (i + 1 == path.size() || path[i + 1] == L'"')) {
       commandLine += L"\\\\";
     } else if (ch == L'"') {
       commandLine += L"\\\"";
diff --git a/HMCLauncher/HMCL/os.h b/HMCLauncher/HMCL/os.h
index 319e2194e..71504d4ed 100644
--- a/HMCLauncher/HMCL/os.h
+++ b/HMCLauncher/HMCL/os.h
@@ -2,6 +2,7 @@
 #include <string>
 #include <windows.h>
 #include <shlobj.h>
+#include <Objbase.h>
 #include "Version.h"
 
 const int MAX_KEY_LENGTH = 255;
@@ -33,8 +34,6 @@ void MyPathAppend(std::wstring &filePath, const std::wstring &more);
 
 void MyPathAddBackslash(std::wstring &filePath);
 
-LSTATUS MyGetTempPath(std::wstring &out);
-
-LSTATUS MyGetTempFileName(const std::wstring &pathName, const std::wstring &prefixString, std::wstring &out);
+LSTATUS MyGetTempFile(const std::wstring &prefixString, const std::wstring &ext, std::wstring &out);
 
 void MyAppendPathToCommandLine(std::wstring &commandLine, const std::wstring &path);
\ No newline at end of file