diff --git a/modules/desktop_capture/linux/mouse_cursor_monitor_x11.cc b/modules/desktop_capture/linux/mouse_cursor_monitor_x11.cc
index 68323a0f86..772ec8b3d5 100644
--- a/modules/desktop_capture/linux/mouse_cursor_monitor_x11.cc
+++ b/modules/desktop_capture/linux/mouse_cursor_monitor_x11.cc
@@ -206,11 +206,12 @@ void MouseCursorMonitorX11::CaptureCursor() {
   std::unique_ptr<DesktopFrame> image(
       new BasicDesktopFrame(DesktopSize(img->width, img->height)));
 
-  uint64_t* src = reinterpret_cast<uint64_t*>(img->pixels);
+  // Xlib stores 32-bit data in longs, even if longs are 64-bits long.
+  unsigned long* src = img->pixels;
   uint32_t* dst = reinterpret_cast<uint32_t*>(image->data());
   uint32_t* dst_end = dst + (img->width * img->height);
   while (dst < dst_end) {
-    *dst++ = *src++;
+    *dst++ = static_cast<uint32_t>(*src++);
   }
 
   DesktopVector hotspot(std::min(img->width, img->xhot),