diff --git a/cpp/autobuilder/Semmle.Autobuild.Cpp.Tests/BuildScripts.cs b/cpp/autobuilder/Semmle.Autobuild.Cpp.Tests/BuildScripts.cs
index 06057b971b5..a3e7987394d 100644
--- a/cpp/autobuilder/Semmle.Autobuild.Cpp.Tests/BuildScripts.cs
+++ b/cpp/autobuilder/Semmle.Autobuild.Cpp.Tests/BuildScripts.cs
@@ -327,7 +327,7 @@ namespace Semmle.Autobuild.Cpp.Tests
         {
             Actions.RunProcess[@"cmd.exe /C nuget restore C:\Project\test.sln -DisableParallelProcessing"] = 1;
             Actions.RunProcess[@"cmd.exe /C C:\Project\.nuget\nuget.exe restore C:\Project\test.sln -DisableParallelProcessing"] = 0;
-            Actions.RunProcess[@"cmd.exe /C CALL ^""C:\Program Files ^(x86^)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat^"" && set Platform=&& type NUL && msbuild C:\Project\test.sln /t:rebuild /p:Platform=""x86"" /p:Configuration=""Release"""] = 0;
+            Actions.RunProcess[@"cmd.exe /C CALL ^""C:\Program^ Files^ ^(x86^)\Microsoft^ Visual^ Studio^ 14.0\VC\vcvarsall.bat^"" && set Platform=&& type NUL && msbuild C:\Project\test.sln /t:rebuild /p:Platform=""x86"" /p:Configuration=""Release"""] = 0;
             Actions.RunProcessOut[@"C:\Program Files (x86)\Microsoft Visual Studio\Installer\vswhere.exe -prerelease -legacy -property installationPath"] = "";
             Actions.RunProcess[@"C:\Program Files (x86)\Microsoft Visual Studio\Installer\vswhere.exe -prerelease -legacy -property installationPath"] = 1;
             Actions.RunProcess[@"C:\Program Files (x86)\Microsoft Visual Studio\Installer\vswhere.exe -prerelease -legacy -property installationVersion"] = 0;
diff --git a/csharp/autobuilder/Semmle.Autobuild.CSharp.Tests/BuildScripts.cs b/csharp/autobuilder/Semmle.Autobuild.CSharp.Tests/BuildScripts.cs
index 9590e132229..fb07ae02f60 100644
--- a/csharp/autobuilder/Semmle.Autobuild.CSharp.Tests/BuildScripts.cs
+++ b/csharp/autobuilder/Semmle.Autobuild.CSharp.Tests/BuildScripts.cs
@@ -725,7 +725,7 @@ namespace Semmle.Autobuild.CSharp.Tests
         [Fact]
         public void TestWindowsCmdIgnoreErrors()
         {
-            actions.RunProcess["cmd.exe /C ^\"build.cmd --skip-tests^\""] = 3;
+            actions.RunProcess["cmd.exe /C ^\"build.cmd^ --skip-tests^\""] = 3;
             actions.RunProcess[@"cmd.exe /C C:\codeql\tools\java\bin\java -jar C:\codeql\csharp\tools\extractor-asp.jar ."] = 0;
             actions.RunProcess[@"cmd.exe /C C:\codeql\tools\codeql index --xml --extensions config"] = 0;
             actions.FileExists["csharp.log"] = true;
@@ -744,9 +744,9 @@ namespace Semmle.Autobuild.CSharp.Tests
         public void TestWindowCSharpMsBuild()
         {
             actions.RunProcess[@"cmd.exe /C C:\Project\.nuget\nuget.exe restore C:\Project\test1.sln -DisableParallelProcessing"] = 0;
-            actions.RunProcess["cmd.exe /C CALL ^\"C:\\Program Files ^(x86^)\\Microsoft Visual Studio 12.0\\VC\\vcvarsall.bat^\" && set Platform=&& type NUL && msbuild C:\\Project\\test1.sln /t:Windows /p:Platform=\"x86\" /p:Configuration=\"Debug\" /P:Fu=Bar"] = 0;
+            actions.RunProcess["cmd.exe /C CALL ^\"C:\\Program^ Files^ ^(x86^)\\Microsoft^ Visual^ Studio^ 12.0\\VC\\vcvarsall.bat^\" && set Platform=&& type NUL && msbuild C:\\Project\\test1.sln /t:Windows /p:Platform=\"x86\" /p:Configuration=\"Debug\" /P:Fu=Bar"] = 0;
             actions.RunProcess[@"cmd.exe /C C:\Project\.nuget\nuget.exe restore C:\Project\test2.sln -DisableParallelProcessing"] = 0;
-            actions.RunProcess["cmd.exe /C CALL ^\"C:\\Program Files ^(x86^)\\Microsoft Visual Studio 12.0\\VC\\vcvarsall.bat^\" && set Platform=&& type NUL && msbuild C:\\Project\\test2.sln /t:Windows /p:Platform=\"x86\" /p:Configuration=\"Debug\" /P:Fu=Bar"] = 0;
+            actions.RunProcess["cmd.exe /C CALL ^\"C:\\Program^ Files^ ^(x86^)\\Microsoft^ Visual^ Studio^ 12.0\\VC\\vcvarsall.bat^\" && set Platform=&& type NUL && msbuild C:\\Project\\test2.sln /t:Windows /p:Platform=\"x86\" /p:Configuration=\"Debug\" /P:Fu=Bar"] = 0;
             actions.FileExists["csharp.log"] = true;
             actions.FileExists[@"C:\Program Files (x86)\Microsoft Visual Studio\Installer\vswhere.exe"] = false;
             actions.FileExists[@"C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat"] = false;
@@ -775,9 +775,9 @@ namespace Semmle.Autobuild.CSharp.Tests
         public void TestWindowCSharpMsBuildMultipleSolutions()
         {
             actions.RunProcess[@"cmd.exe /C nuget restore C:\Project\test1.csproj -DisableParallelProcessing"] = 0;
-            actions.RunProcess["cmd.exe /C CALL ^\"C:\\Program Files ^(x86^)\\Microsoft Visual Studio 12.0\\VC\\vcvarsall.bat^\" && set Platform=&& type NUL && msbuild C:\\Project\\test1.csproj /t:Windows /p:Platform=\"x86\" /p:Configuration=\"Debug\" /P:Fu=Bar"] = 0;
+            actions.RunProcess["cmd.exe /C CALL ^\"C:\\Program^ Files^ ^(x86^)\\Microsoft^ Visual^ Studio^ 12.0\\VC\\vcvarsall.bat^\" && set Platform=&& type NUL && msbuild C:\\Project\\test1.csproj /t:Windows /p:Platform=\"x86\" /p:Configuration=\"Debug\" /P:Fu=Bar"] = 0;
             actions.RunProcess[@"cmd.exe /C nuget restore C:\Project\test2.csproj -DisableParallelProcessing"] = 0;
-            actions.RunProcess["cmd.exe /C CALL ^\"C:\\Program Files ^(x86^)\\Microsoft Visual Studio 12.0\\VC\\vcvarsall.bat^\" && set Platform=&& type NUL && msbuild C:\\Project\\test2.csproj /t:Windows /p:Platform=\"x86\" /p:Configuration=\"Debug\" /P:Fu=Bar"] = 0;
+            actions.RunProcess["cmd.exe /C CALL ^\"C:\\Program^ Files^ ^(x86^)\\Microsoft^ Visual^ Studio^ 12.0\\VC\\vcvarsall.bat^\" && set Platform=&& type NUL && msbuild C:\\Project\\test2.csproj /t:Windows /p:Platform=\"x86\" /p:Configuration=\"Debug\" /P:Fu=Bar"] = 0;
             actions.FileExists["csharp.log"] = true;
             actions.FileExists[@"C:\Project\test1.csproj"] = true;
             actions.FileExists[@"C:\Project\test2.csproj"] = true;
@@ -820,7 +820,7 @@ namespace Semmle.Autobuild.CSharp.Tests
         public void TestWindowCSharpMsBuildFailed()
         {
             actions.RunProcess[@"cmd.exe /C nuget restore C:\Project\test1.sln -DisableParallelProcessing"] = 0;
-            actions.RunProcess["cmd.exe /C CALL ^\"C:\\Program Files ^(x86^)\\Microsoft Visual Studio 12.0\\VC\\vcvarsall.bat^\" && set Platform=&& type NUL && msbuild C:\\Project\\test1.sln /t:Windows /p:Platform=\"x86\" /p:Configuration=\"Debug\" /P:Fu=Bar"] = 1;
+            actions.RunProcess["cmd.exe /C CALL ^\"C:\\Program^ Files^ ^(x86^)\\Microsoft^ Visual^ Studio^ 12.0\\VC\\vcvarsall.bat^\" && set Platform=&& type NUL && msbuild C:\\Project\\test1.sln /t:Windows /p:Platform=\"x86\" /p:Configuration=\"Debug\" /P:Fu=Bar"] = 1;
             actions.FileExists["csharp.log"] = true;
             actions.FileExists[@"C:\Program Files (x86)\Microsoft Visual Studio\Installer\vswhere.exe"] = false;
             actions.FileExists[@"C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat"] = false;
@@ -846,8 +846,8 @@ namespace Semmle.Autobuild.CSharp.Tests
         [Fact]
         public void TestSkipNugetMsBuild()
         {
-            actions.RunProcess["cmd.exe /C CALL ^\"C:\\Program Files ^(x86^)\\Microsoft Visual Studio 12.0\\VC\\vcvarsall.bat^\" && set Platform=&& type NUL && msbuild C:\\Project\\test1.sln /t:Windows /p:Platform=\"x86\" /p:Configuration=\"Debug\" /P:Fu=Bar"] = 0;
-            actions.RunProcess["cmd.exe /C CALL ^\"C:\\Program Files ^(x86^)\\Microsoft Visual Studio 12.0\\VC\\vcvarsall.bat^\" && set Platform=&& type NUL && msbuild C:\\Project\\test2.sln /t:Windows /p:Platform=\"x86\" /p:Configuration=\"Debug\" /P:Fu=Bar"] = 0;
+            actions.RunProcess["cmd.exe /C CALL ^\"C:\\Program^ Files^ ^(x86^)\\Microsoft^ Visual^ Studio^ 12.0\\VC\\vcvarsall.bat^\" && set Platform=&& type NUL && msbuild C:\\Project\\test1.sln /t:Windows /p:Platform=\"x86\" /p:Configuration=\"Debug\" /P:Fu=Bar"] = 0;
+            actions.RunProcess["cmd.exe /C CALL ^\"C:\\Program^ Files^ ^(x86^)\\Microsoft^ Visual^ Studio^ 12.0\\VC\\vcvarsall.bat^\" && set Platform=&& type NUL && msbuild C:\\Project\\test2.sln /t:Windows /p:Platform=\"x86\" /p:Configuration=\"Debug\" /P:Fu=Bar"] = 0;
             actions.FileExists["csharp.log"] = true;
             actions.FileExists[@"C:\Program Files (x86)\Microsoft Visual Studio\Installer\vswhere.exe"] = false;
             actions.FileExists[@"C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat"] = false;
@@ -1037,7 +1037,7 @@ namespace Semmle.Autobuild.CSharp.Tests
         {
             actions.RunProcess[@"cmd.exe /C nuget restore C:\Project\dirs.proj -DisableParallelProcessing"] = 1;
             actions.RunProcess[@"cmd.exe /C C:\Project\.nuget\nuget.exe restore C:\Project\dirs.proj -DisableParallelProcessing"] = 0;
-            actions.RunProcess["cmd.exe /C CALL ^\"C:\\Program Files ^(x86^)\\Microsoft Visual Studio 12.0\\VC\\vcvarsall.bat^\" && set Platform=&& type NUL && msbuild C:\\Project\\dirs.proj /t:Windows /p:Platform=\"x86\" /p:Configuration=\"Debug\" /P:Fu=Bar"] = 0;
+            actions.RunProcess["cmd.exe /C CALL ^\"C:\\Program^ Files^ ^(x86^)\\Microsoft^ Visual^ Studio^ 12.0\\VC\\vcvarsall.bat^\" && set Platform=&& type NUL && msbuild C:\\Project\\dirs.proj /t:Windows /p:Platform=\"x86\" /p:Configuration=\"Debug\" /P:Fu=Bar"] = 0;
             actions.FileExists["csharp.log"] = true;
             actions.FileExists[@"C:\Project\a\test.csproj"] = true;
             actions.FileExists[@"C:\Project\dirs.proj"] = true;
diff --git a/csharp/autobuilder/Semmle.Autobuild.Shared/CommandBuilder.cs b/csharp/autobuilder/Semmle.Autobuild.Shared/CommandBuilder.cs
index 2064380772f..263f35f2fff 100644
--- a/csharp/autobuilder/Semmle.Autobuild.Shared/CommandBuilder.cs
+++ b/csharp/autobuilder/Semmle.Autobuild.Shared/CommandBuilder.cs
@@ -55,7 +55,7 @@ namespace Semmle.Autobuild.Shared
         }
 
         private static readonly char[] specialChars = { ' ', '\t', '\n', '\v', '\"' };
-        private static readonly char[] cmdMetacharacter = { '(', ')', '%', '!', '^', '\"', '<', '>', '&', '|' };
+        private static readonly char[] cmdMetacharacter = { '(', ')', '%', '!', '^', '\"', '<', '>', '&', '|', ' ' };
 
         /// <summary>
         /// Appends the given argument to the command line.