Index: /trunk/src/VBox/Storage/VD.cpp
===================================================================
--- /trunk/src/VBox/Storage/VD.cpp	(revision 53336)
+++ /trunk/src/VBox/Storage/VD.cpp	(revision 53337)
@@ -3076,4 +3076,5 @@
                 if (RT_FAILURE(rc) && (rc != VERR_VD_ASYNC_IO_IN_PROGRESS))
                 {
+                    vdIoCtxUnlockDisk(pDisk, pIoCtx, false /* fProcessDeferredReqs*/ );
                     vdIoCtxFree(pDisk, pIoCtxWrite);
                     break;