diff --git a/code/client/citicore/SEHTableHandler.Win32.cpp b/code/client/citicore/SEHTableHandler.Win32.cpp
index d413b35d20..6a0aaa122f 100644
--- a/code/client/citicore/SEHTableHandler.Win32.cpp
+++ b/code/client/citicore/SEHTableHandler.Win32.cpp
@@ -14,6 +14,8 @@
 
 #include <udis86.h>
 
+#include <LaunchMode.h>
+
 static void* FindCallFromAddress(void* methodPtr, ud_mnemonic_code mnemonic = UD_Icall, bool breakOnFirst = false)
 {
 	// return value holder
@@ -210,7 +212,8 @@ extern "C" void DLL_EXPORT CoreRT_SetupSEHHandler(void* moduleBase, void* module
 			if (!internalAddress)
 			{
 				// and 2k3 to 7 don't even _have_ Rtlpx - so we directly hook the Rtl* function
-				if (IsWindows8OrGreater())
+				// (Wine's ntdll doesn't match real ntdll's binary layout, so it never finds RtlpxLookupFunctionTable there either. Treat it like a downlevel OS)
+				if (IsWindows8OrGreater() && !CfxIsWine())
 				{
 					FatalError("Could not find RtlpxLookupFunctionTable - hooking RtlLookupFunctionTable directly. This will break on a Win8+ system since RtlpxLookupFunctionTable is supposed to exist!\n");
 				}
diff --git a/code/client/launcher/UpdaterUI.cpp b/code/client/launcher/UpdaterUI.cpp
index c7c5264d52..80a524e0af 100644
--- a/code/client/launcher/UpdaterUI.cpp
+++ b/code/client/launcher/UpdaterUI.cpp
@@ -15,6 +15,8 @@
 
 #include "launcher.rc.h"
 
+#include <../citicore/LaunchMode.h>
+
 #include <ShellScalingApi.h>
 
 #include <winrt/Windows.Storage.Streams.h>
@@ -1333,6 +1335,12 @@ std::unique_ptr<TenUIBase> UI_InitTen()
 		forceOff = true;
 	}
 
+	if (CfxIsWine())
+	{
+		// WinRT XAML Islands not implemented in Wine/Proton, fall back to the plain Win32 controls UI.
+		forceOff = true;
+	}
+
 #ifdef IS_LAUNCHER
 	forceOff = true;
 #endif