diff --git a/BeefLibs/corlib/src/IO/OpenFileDialog.bf b/BeefLibs/corlib/src/IO/OpenFileDialog.bf
index bb8cb5f2..3697c1c5 100644
--- a/BeefLibs/corlib/src/IO/OpenFileDialog.bf
+++ b/BeefLibs/corlib/src/IO/OpenFileDialog.bf
@@ -425,7 +425,7 @@ namespace System.IO
 			ofn.mCustData = (int)Internal.UnsafeCastToPtr(this);
 	        ofn.mFlagsEx = Windows.OFN_USESHELLITEM;
 	        if (mDefaultExt != null && AddExtension)
-	            ofn.mDefExt = mDefaultExt;
+	            ofn.mDefExt = mDefaultExt.ToScopedNativeWChar!::();
 
 			DeleteContainerAndItems!(mFileNames);
 			mFileNames = null;
diff --git a/BeefLibs/corlib/src/Windows.bf b/BeefLibs/corlib/src/Windows.bf
index 36f2e8c3..e1d1848c 100644
--- a/BeefLibs/corlib/src/Windows.bf
+++ b/BeefLibs/corlib/src/Windows.bf
@@ -120,7 +120,7 @@ namespace System
 			public int32 mFlags;
 			public int16 mFileOffset = 0;
 			public int16 mFileExtension = 0;
-			public char8* mDefExt;
+			public char16* mDefExt;
 			public int mCustData = 0;
 			public WndProc mHook;
 			public char16* mTemplateName = null;