Index: /trunk/src/VBox/VMM/PDMAsyncCompletionFile.cpp
===================================================================
--- /trunk/src/VBox/VMM/PDMAsyncCompletionFile.cpp	(revision 30296)
+++ /trunk/src/VBox/VMM/PDMAsyncCompletionFile.cpp	(revision 30297)
@@ -898,5 +898,13 @@
                 pEpFile->pBwMgr         = pEpClassFile->pBwMgr;
                 pEpFile->enmBackendType = enmEpBackend;
+                /*
+                 * Disable async flushes on Solaris for now.
+                 * They cause weird hangs which needs more investigations.
+                 */
+#ifndef RT_OS_SOLARIS
                 pEpFile->fAsyncFlushSupported = true;
+#else
+                pEpFile->fAsyncFlushSupported = false;
+#endif
                 pdmacFileBwRef(pEpFile->pBwMgr);