Use Windows MessageBox API for error when GLFW can't create a Window.

internal/driver/glfw/driver.go

@@ -141,7 +141,7 @@ func (d *gLDriver) windowList() []fyne.Window {
 }
 
 func (d *gLDriver) initFailed(msg string, err error) {
-	fyne.LogError(msg, err)
+	logError(msg, err)
 
 	run.Lock()
 	if !run.flag {

internal/driver/glfw/driver_notwindows.go

@@ -0,0 +1,10 @@
+//go:build !windows
+// +build !windows
+
+package glfw
+
+import "fyne.io/fyne/v2"
+
+func logError(msg string, err error) {
+	fyne.LogError(msg, err)
+}

internal/driver/glfw/driver_windows.go

@@ -0,0 +1,50 @@
+package glfw
+
+import (
+	"fmt"
+	"runtime"
+	"syscall"
+	"unsafe"
+)
+
+type MB uint32
+
+const (
+	MB_OK        MB = 0x0000_0000
+	MB_ICONERROR MB = 0x0000_0010
+)
+
+func toNativePtr(s string) *uint16 {
+	pstr, err := syscall.UTF16PtrFromString(s)
+	if err != nil {
+		panic(fmt.Sprintf("toNativePtr() failed \"%s\": %s", s, err))
+	}
+	return pstr
+}
+
+// https://docs.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-messageboxw
+func messageBoxError(text, caption string) {
+	user32 := syscall.NewLazyDLL("user32.dll")
+	MessageBox := user32.NewProc("MessageBoxW")
+
+	uType := MB_OK | MB_ICONERROR
+
+	syscall.Syscall6(MessageBox.Addr(), 4,
+		uintptr(unsafe.Pointer(nil)), uintptr(unsafe.Pointer(toNativePtr(text))),
+		uintptr(unsafe.Pointer(toNativePtr(caption))), uintptr(uType),
+		0, 0)
+}
+
+func logError(msg string, err error) {
+	text := fmt.Sprintf("Fyne error: %v", msg)
+	if err != nil {
+		text = text + fmt.Sprintf("\n  Cause:%v", err)
+	}
+
+	_, file, line, ok := runtime.Caller(1)
+	if ok {
+		text = text + fmt.Sprintf("\n  At: %s:%d", file, line)
+	}
+
+	messageBoxError(text, "Fyne Error")
+}