Index: lldb/trunk/packages/Python/lldbsuite/test/functionalities/process_launch/TestProcessLaunch.py
===================================================================
--- lldb/trunk/packages/Python/lldbsuite/test/functionalities/process_launch/TestProcessLaunch.py
+++ lldb/trunk/packages/Python/lldbsuite/test/functionalities/process_launch/TestProcessLaunch.py
@@ -85,7 +85,34 @@
     # not working?
     @not_remote_testsuite_ready
     @expectedFailureAll(oslist=["linux"], bugnumber="llvm.org/pr20265")
-    def test_set_working_dir(self):
+    def test_set_working_dir_nonexisting(self):
+        """Test that '-w dir' fails to set the working dir when running the inferior with a dir which doesn't exist."""
+        d = {'CXX_SOURCES': 'print_cwd.cpp'}
+        self.build(dictionary=d)
+        self.setTearDownCleanup(d)
+        exe = self.getBuildArtifact("a.out")
+        self.runCmd("file " + exe)
+
+        mywd = 'my_working_dir'
+        out_file_name = "my_working_dir_test.out"
+        err_file_name = "my_working_dir_test.err"
+
+        my_working_dir_path = self.getBuildArtifact(mywd)
+        out_file_path = os.path.join(my_working_dir_path, out_file_name)
+        err_file_path = os.path.join(my_working_dir_path, err_file_name)
+
+        # Check that we get an error when we have a nonexisting path
+        invalid_dir_path = mywd + 'z'
+        launch_command = "process launch -w %s -o %s -e %s" % (
+            invalid_dir_path, out_file_path, err_file_path)
+
+        self.expect(
+            launch_command, error=True, patterns=[
+                "error:.* No such file or directory: %s" %
+                invalid_dir_path])
+
+    @not_remote_testsuite_ready
+    def test_set_working_dir_existing(self):
         """Test that '-w dir' sets the working dir when running the inferior."""
         d = {'CXX_SOURCES': 'print_cwd.cpp'}
         self.build(dictionary=d)
@@ -109,16 +136,6 @@
         except OSError:
             pass
 
-        # Check that we get an error when we have a nonexisting path
-        launch_command = "process launch -w %s -o %s -e %s" % (
-            my_working_dir_path + 'z', out_file_path, err_file_path)
-
-        self.expect(
-            launch_command, error=True, patterns=[
-                "error:.* No such file or directory: %sz" %
-                my_working_dir_path])
-
-        # Really launch the process
         launch_command = "process launch -w %s -o %s -e %s" % (
             my_working_dir_path, out_file_path, err_file_path)
 
Index: lldb/trunk/packages/Python/lldbsuite/test/lldbtest.py
===================================================================
--- lldb/trunk/packages/Python/lldbsuite/test/lldbtest.py
+++ lldb/trunk/packages/Python/lldbsuite/test/lldbtest.py
@@ -1833,7 +1833,7 @@
 
     # Maximum allowed attempts when launching the inferior process.
     # Can be overridden by the LLDB_MAX_LAUNCH_COUNT environment variable.
-    maxLaunchCount = 3
+    maxLaunchCount = 1
 
     # Time to wait before the next launching attempt in second(s).
     # Can be overridden by the LLDB_TIME_WAIT_NEXT_LAUNCH environment variable.
Index: lldb/trunk/source/Host/windows/ProcessLauncherWindows.cpp
===================================================================
--- lldb/trunk/source/Host/windows/ProcessLauncherWindows.cpp
+++ lldb/trunk/source/Host/windows/ProcessLauncherWindows.cpp
@@ -96,6 +96,12 @@
       wexecutable.c_str(), &wcommandLine[0], NULL, NULL, TRUE, flags, env_block,
       wworkingDirectory.size() == 0 ? NULL : wworkingDirectory.c_str(),
       &startupinfo, &pi);
+
+  if (!result) {
+    // Call GetLastError before we make any other system calls.
+    error.SetError(::GetLastError(), eErrorTypeWin32);
+  }
+
   if (result) {
     // Do not call CloseHandle on pi.hProcess, since we want to pass that back
     // through the HostProcess.
@@ -110,7 +116,8 @@
     ::CloseHandle(stderr_handle);
 
   if (!result)
-    error.SetError(::GetLastError(), eErrorTypeWin32);
+    return HostProcess();
+
   return HostProcess(pi.hProcess);
 }
 
Index: lldb/trunk/source/Plugins/Process/Windows/Common/DebuggerThread.cpp
===================================================================
--- lldb/trunk/source/Plugins/Process/Windows/Common/DebuggerThread.cpp
+++ lldb/trunk/source/Plugins/Process/Windows/Common/DebuggerThread.cpp
@@ -181,13 +181,19 @@
   lldb::process_t handle = m_process.GetNativeProcess().GetSystemHandle();
 
   if (terminate) {
-    // Initiate the termination before continuing the exception, so that the
-    // next debug event we get is the exit process event, and not some other
-    // event.
-    BOOL terminate_suceeded = TerminateProcess(handle, 0);
-    LLDB_LOG(log,
-             "calling TerminateProcess({0}, 0) (inferior={1}), success={2}",
-             handle, pid, terminate_suceeded);
+    if (handle != nullptr && handle != LLDB_INVALID_PROCESS) {
+      // Initiate the termination before continuing the exception, so that the
+      // next debug event we get is the exit process event, and not some other
+      // event.
+      BOOL terminate_suceeded = TerminateProcess(handle, 0);
+      LLDB_LOG(log,
+               "calling TerminateProcess({0}, 0) (inferior={1}), success={2}",
+               handle, pid, terminate_suceeded);
+    } else {
+      LLDB_LOG(log,
+               "NOT calling TerminateProcess because the inferior is not valid ({0}, 0) (inferior={1})",
+               handle, pid);
+    }
   }
 
   // If we're stuck waiting for an exception to continue (e.g. the user is at a
Index: lldb/trunk/source/Plugins/Process/Windows/Common/ProcessWindows.cpp
===================================================================
--- lldb/trunk/source/Plugins/Process/Windows/Common/ProcessWindows.cpp
+++ lldb/trunk/source/Plugins/Process/Windows/Common/ProcessWindows.cpp
@@ -234,6 +234,16 @@
 
   Log *log = ProcessWindowsLog::GetLogIfAny(WINDOWS_LOG_PROCESS);
   Status result;
+
+  FileSpec working_dir = launch_info.GetWorkingDirectory();
+  namespace fs = llvm::sys::fs;
+  if (working_dir && (!working_dir.ResolvePath() ||
+                      !fs::is_directory(working_dir.GetPath()))) {
+    result.SetErrorStringWithFormat("No such file or directory: %s",
+                                   working_dir.GetCString());
+    return result;
+  }
+
   if (!launch_info.GetFlags().Test(eLaunchFlagDebug)) {
     StreamString stream;
     stream.Printf("ProcessWindows unable to launch '%s'.  ProcessWindows can "