diff --git a/libvo/vo_vdpau.c b/libvo/vo_vdpau.c
index 83955f5ff3..f482533ff6 100644
--- a/libvo/vo_vdpau.c
+++ b/libvo/vo_vdpau.c
@@ -375,6 +375,7 @@ static int win_x11_init_vdpau_procs(void)
         return -1;
     }
 
+    vdp_get_error_string = NULL;
     for (dsc = vdp_func; dsc->pointer; dsc++) {
         vdp_st = vdp_get_proc_address(vdp_device, dsc->id, dsc->pointer);
         if (vdp_st != VDP_STATUS_OK) {