diff --git a/.appveyor.yml b/.appveyor.yml
index d166a46..d2ea51c 100644
--- a/.appveyor.yml
+++ b/.appveyor.yml
@@ -40,7 +40,7 @@ environment:
   OGG_MSBUILD_CMD_X64: /maxcpucount /property:Configuration=Release,Platform=x64   /target:ogg
 
   OPUS_SOL_FILE: Opus.sln
-  OPUS_GIT_TAG: v1.3.1
+  #OPUS_GIT_TAG: v1.3.1
   OPUS_MSBUILD_CMD_X86: /maxcpucount /property:Configuration=Release,Platform=Win32
   OPUS_MSBUILD_CMD_X64: /maxcpucount /property:Configuration=Release,Platform=x64
 
@@ -57,11 +57,11 @@ environment:
 
   NASM_URL: https://www.nasm.us/pub/nasm/releasebuilds/2.15.05/win64/nasm-2.15.05-win64.zip
 
-  FLAC_SOL_FILE: FLAC.sln
+  FLAC_SOL_FILE: src\libFLAC++\FLAC++.vcxproj
   FLAC_CMAKE_X86: -DOGG_INCLUDE_DIR="%REPO_DIR%\lib\libogg\include" -DOGG_LIBRARY="%REPO_DIR%\lib\libogg\_build\Win32\Release\ogg.lib"
   FLAC_CMAKE_X64: -DOGG_INCLUDE_DIR="%REPO_DIR%\lib\libogg\include" -DOGG_LIBRARY="%REPO_DIR%\lib\libogg\_build\x64\Release\ogg.lib"
-  FLAC_MSBUILD_CMD_X86: /maxcpucount /property:Configuration=Release,Platform=Win32 /target:FLAC++
-  FLAC_MSBUILD_CMD_X64: /maxcpucount /property:Configuration=Release,Platform=x64   /target:FLAC++
+  FLAC_MSBUILD_CMD_X86: /maxcpucount /property:Configuration=Release,Platform=Win32
+  FLAC_MSBUILD_CMD_X64: /maxcpucount /property:Configuration=Release,Platform=x64
 
   OPUS-TOOLS_SOL_FILE: opus-tools.sln
   OPUS-TOOLS_MSBUILD_CMD_X86: /maxcpucount /property:Configuration=Release,Platform=Win32
@@ -95,7 +95,7 @@ before_build:
 
   # prepare opus
   - cd "%REPO_DIR%\lib\opus"
-  - git checkout tags/%OPUS_GIT_TAG%
+  #- git checkout tags/%OPUS_GIT_TAG%
   - mkdir "_build" && cd "_build"
   - mkdir "Win32" && cd "Win32"
   - cmake %CMAKE_GENERATOR_X86% %CMAKE_COMMON_DEFINES% ..\..\
@@ -138,7 +138,6 @@ before_build:
 
   # prepare flac
   - cd "%REPO_DIR%\lib\flac"
-  - ps: (Get-Content 'src\libFLAC\ia32\CMakeLists.txt') | ForEach-Object { $_ -replace '^#include_directories', 'include_directories' } | Set-Content 'src\libFLAC\ia32\CMakeLists.txt'
   - mkdir "_build" && cd "_build"
   - mkdir "Win32" && cd "Win32"
   - cmake %CMAKE_GENERATOR_X86% %CMAKE_COMMON_DEFINES% %FLAC_CMAKE_X86% ..\..\
diff --git a/src/libopusenc/VS2015/opusenc.vcxproj b/src/libopusenc/VS2015/opusenc.vcxproj
index 97faced..1bf00a8 100644
--- a/src/libopusenc/VS2015/opusenc.vcxproj
+++ b/src/libopusenc/VS2015/opusenc.vcxproj
@@ -157,6 +157,7 @@
     <Link>
       <AdditionalLibraryDirectories Condition="'$(Configuration)|$(Platform)'=='ReleaseDLL|Win32'">..\..\..\opus\win32\VS2015\$(Platform)\$(Configuration)</AdditionalLibraryDirectories>
       <AdditionalDependencies Condition="'$(Configuration)|$(Platform)'=='ReleaseDLL|Win32'">opus.lib;kernel32.lib;user32.lib;gdi32.lib;winspool.lib;comdlg32.lib;advapi32.lib;shell32.lib;ole32.lib;oleaut32.lib;uuid.lib;odbc32.lib;odbccp32.lib;%(AdditionalDependencies)</AdditionalDependencies>
+      <ControlFlowGuard Condition="'$(Configuration)|$(Platform)'=='ReleaseDLL|Win32'">Guard</ControlFlowGuard>
     </Link>
     <Link>
       <AdditionalLibraryDirectories Condition="'$(Configuration)|$(Platform)'=='DebugDLL|x64'">..\..\..\opus\win32\VS2015\$(Platform)\$(Configuration)</AdditionalLibraryDirectories>
@@ -165,12 +166,15 @@
     <Link>
       <AdditionalLibraryDirectories Condition="'$(Configuration)|$(Platform)'=='ReleaseDLL|x64'">..\..\..\opus\win32\VS2015\$(Platform)\$(Configuration)</AdditionalLibraryDirectories>
       <AdditionalDependencies Condition="'$(Configuration)|$(Platform)'=='ReleaseDLL|x64'">opus.lib;kernel32.lib;user32.lib;gdi32.lib;winspool.lib;comdlg32.lib;advapi32.lib;shell32.lib;ole32.lib;oleaut32.lib;uuid.lib;odbc32.lib;odbccp32.lib;%(AdditionalDependencies)</AdditionalDependencies>
+      <ControlFlowGuard Condition="'$(Configuration)|$(Platform)'=='ReleaseDLL|x64'">Guard</ControlFlowGuard>
     </Link>
     <ClCompile>
       <AdditionalOptions Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">/Gw %(AdditionalOptions)</AdditionalOptions>
+      <ControlFlowGuard Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">Guard</ControlFlowGuard>
     </ClCompile>
     <ClCompile>
       <AdditionalOptions Condition="'$(Configuration)|$(Platform)'=='Release|x64'">/Gw %(AdditionalOptions)</AdditionalOptions>
+      <ControlFlowGuard Condition="'$(Configuration)|$(Platform)'=='Release|x64'">Guard</ControlFlowGuard>
     </ClCompile>
   </ItemDefinitionGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
diff --git a/src/opus-tools/VS2015/common.props b/src/opus-tools/VS2015/common.props
index 6a2a56b..60e9005 100644
--- a/src/opus-tools/VS2015/common.props
+++ b/src/opus-tools/VS2015/common.props
@@ -11,6 +11,7 @@
     <WholeProgramOptimization>false</WholeProgramOptimization>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)'=='Release' or '$(Configuration)'=='ReleaseDLL' or '$(Configuration)'=='ReleaseDLL_fixed'">
+    <ControlFlowGuard>Guard</ControlFlowGuard>
     <WholeProgramOptimization>true</WholeProgramOptimization>
   </PropertyGroup>
   <ItemDefinitionGroup>
diff --git a/src/opusfile/VS2015/opusfile.vcxproj b/src/opusfile/VS2015/opusfile.vcxproj
index d5f144b..ece5244 100644
--- a/src/opusfile/VS2015/opusfile.vcxproj
+++ b/src/opusfile/VS2015/opusfile.vcxproj
@@ -159,6 +159,7 @@
       <FloatingPointModel>Fast</FloatingPointModel>
       <AdditionalOptions>/Gw %(AdditionalOptions)</AdditionalOptions>
       <AdditionalIncludeDirectories>..\..\..\openssl\include;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
+      <ControlFlowGuard>Guard</ControlFlowGuard>
     </ClCompile>
     <Link>
       <SubSystem>Windows</SubSystem>
@@ -176,6 +177,7 @@
       <RuntimeLibrary>MultiThreaded</RuntimeLibrary>
       <FloatingPointModel>Fast</FloatingPointModel>
       <AdditionalOptions>/Gw %(AdditionalOptions)</AdditionalOptions>
+      <ControlFlowGuard>Guard</ControlFlowGuard>
     </ClCompile>
     <Link>
       <SubSystem>Windows</SubSystem>
@@ -194,6 +196,7 @@
       <FloatingPointModel>Fast</FloatingPointModel>
       <AdditionalOptions>/Gw %(AdditionalOptions)</AdditionalOptions>
       <AdditionalIncludeDirectories>..\..\..\openssl\include;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
+      <ControlFlowGuard>Guard</ControlFlowGuard>
     </ClCompile>
     <Link>
       <SubSystem>Windows</SubSystem>
@@ -211,6 +214,7 @@
       <RuntimeLibrary>MultiThreaded</RuntimeLibrary>
       <FloatingPointModel>Fast</FloatingPointModel>
       <AdditionalOptions>/Gw %(AdditionalOptions)</AdditionalOptions>
+      <ControlFlowGuard>Guard</ControlFlowGuard>
     </ClCompile>
     <Link>
       <SubSystem>Windows</SubSystem>