Index: /trunk/src/VBox/VMM/PDMAsyncCompletionFile.cpp
===================================================================
--- /trunk/src/VBox/VMM/PDMAsyncCompletionFile.cpp	(revision 29449)
+++ /trunk/src/VBox/VMM/PDMAsyncCompletionFile.cpp	(revision 29450)
@@ -632,9 +632,5 @@
 
             /* Query default backend type */
-#ifndef RT_OS_LINUX
-            rc = CFGMR3QueryStringAllocDef(pCfgNode, "FileBackend", &pszVal, "Buffered");
-#else /* Linux can't use buffered with async */
             rc = CFGMR3QueryStringAllocDef(pCfgNode, "FileBackend", &pszVal, "NonBuffered");
-#endif
             AssertLogRelRCReturn(rc, rc);
 
@@ -658,10 +654,5 @@
         {
             /* No configuration supplied, set defaults */
-            pEpClassFile->enmMgrTypeOverride = PDMACEPFILEMGRTYPE_ASYNC;
-#ifdef RT_OS_LINUX
             pEpClassFile->enmEpBackendDefault = PDMACFILEEPBACKEND_NON_BUFFERED;
-#else
-            pEpClassFile->enmEpBackendDefault = PDMACFILEEPBACKEND_BUFFERED;
-#endif
         }
     }
Index: /trunk/src/VBox/VMM/PDMAsyncCompletionFileNormal.cpp
===================================================================
--- /trunk/src/VBox/VMM/PDMAsyncCompletionFileNormal.cpp	(revision 29449)
+++ /trunk/src/VBox/VMM/PDMAsyncCompletionFileNormal.cpp	(revision 29450)
@@ -1029,4 +1029,6 @@
                     AssertMsg(hReq != NIL_RTFILEAIOREQ, ("Out of request handles\n"));
 
+                    LogFlow(("Flush request %#p\n", hReq));
+
                     rc = RTFileAioReqPrepareFlush(hReq, pEndpoint->File, pCurr);
                     if (RT_FAILURE(rc))
@@ -1071,4 +1073,6 @@
                 AssertRC(rc);
 
+                LogFlow(("Read/Write request %#p\n", hReq));
+
                 if (hReq != NIL_RTFILEAIOREQ)
                 {
@@ -1643,10 +1647,10 @@
                         cReqsWait = pAioMgr->cRequestsActive;
 
-                    LogFlow(("Waiting for %d of %d tasks to complete\n", pAioMgr->cRequestsActive, cReqsWait));
+                    LogFlow(("Waiting for %d of %d tasks to complete\n", 1, cReqsWait));
 
                     rc = RTFileAioCtxWait(pAioMgr->hAioCtx,
-                                          cReqsWait,
+                                          1,
                                           RT_INDEFINITE_WAIT, apReqs,
-                                          RT_ELEMENTS(apReqs), &cReqsCompleted);
+                                          cReqsWait, &cReqsCompleted);
                     if (RT_FAILURE(rc) && (rc != VERR_INTERRUPTED))
                         CHECK_RC(pAioMgr, rc);