diff --git a/ompi/mca/osc/pt2pt/osc_pt2pt.c b/ompi/mca/osc/pt2pt/osc_pt2pt.c
index 8ab07c7c74..409b8bff75 100644
--- a/ompi/mca/osc/pt2pt/osc_pt2pt.c
+++ b/ompi/mca/osc/pt2pt/osc_pt2pt.c
@@ -19,6 +19,7 @@
 #include "osc_pt2pt.h"
 #include "osc_pt2pt_sendreq.h"
 
+#include "opal/runtime/opal_progress.h"
 #include "opal/threads/mutex.h"
 #include "ompi/win/win.h"
 #include "ompi/communicator/communicator.h"
@@ -32,6 +33,10 @@ ompi_osc_pt2pt_module_free(ompi_win_t *win)
     int tmp;
     ompi_osc_pt2pt_module_t *module = P2P_MODULE(win);
 
+    while (OMPI_WIN_EXPOSE_EPOCH & ompi_win_get_mode(win)) {
+        opal_progress();
+    }
+
     /* finish with a barrier */
     if (ompi_group_size(win->w_group) > 1) {
         ret = module->p2p_comm->c_coll.coll_barrier(module->p2p_comm);
diff --git a/ompi/mca/osc/pt2pt/osc_pt2pt_sync.c b/ompi/mca/osc/pt2pt/osc_pt2pt_sync.c
index 3200f46091..4cd4e551ce 100644
--- a/ompi/mca/osc/pt2pt/osc_pt2pt_sync.c
+++ b/ompi/mca/osc/pt2pt/osc_pt2pt_sync.c
@@ -422,7 +422,8 @@ ompi_osc_pt2pt_module_lock(int lock_type,
     assert(lock_type != 0);
 
     /* set our mode on the window */
-    ompi_win_set_mode(win, OMPI_WIN_ACCESS_EPOCH | OMPI_WIN_LOCK_ACCESS);
+    ompi_win_remove_mode(win, OMPI_WIN_FENCE);
+    ompi_win_append_mode(win, OMPI_WIN_ACCESS_EPOCH | OMPI_WIN_LOCK_ACCESS);
 
     opal_output_verbose(50, ompi_osc_base_output,
                         "%d sending lock request to %d", 
@@ -493,7 +494,7 @@ ompi_osc_pt2pt_module_unlock(int target,
                                 out_count);
 
     /* set our mode on the window */
-    ompi_win_set_mode(win, 0);
+    ompi_win_remove_mode(win, OMPI_WIN_ACCESS_EPOCH | OMPI_WIN_LOCK_ACCESS);
 
     return OMPI_SUCCESS;
 }
@@ -513,6 +514,7 @@ ompi_osc_pt2pt_passive_lock(ompi_osc_pt2pt_module_t *module,
     if (lock_type == MPI_LOCK_EXCLUSIVE) {
         if (module->p2p_lock_status == 0) {
             module->p2p_lock_status = MPI_LOCK_EXCLUSIVE;
+            ompi_win_append_mode(module->p2p_win, OMPI_WIN_EXPOSE_EPOCH);
             send_ack = true;
         } else {
             opal_output_verbose(50, ompi_osc_base_output,
@@ -527,6 +529,7 @@ ompi_osc_pt2pt_passive_lock(ompi_osc_pt2pt_module_t *module,
         if (module->p2p_lock_status != MPI_LOCK_EXCLUSIVE) {
             module->p2p_lock_status = MPI_LOCK_SHARED;
             module->p2p_shared_count++;
+            ompi_win_append_mode(module->p2p_win, OMPI_WIN_EXPOSE_EPOCH);
             send_ack = true;
         } else {
             opal_output_verbose(50, ompi_osc_base_output,
@@ -573,10 +576,12 @@ ompi_osc_pt2pt_passive_unlock(ompi_osc_pt2pt_module_t *module,
 
     OPAL_THREAD_LOCK(&(module->p2p_lock));
     if (module->p2p_lock_status == MPI_LOCK_EXCLUSIVE) {
+        ompi_win_remove_mode(module->p2p_win, OMPI_WIN_EXPOSE_EPOCH);
         module->p2p_lock_status = 0;
     } else {
         module->p2p_shared_count--;
         if (module->p2p_shared_count == 0) {
+            ompi_win_remove_mode(module->p2p_win, OMPI_WIN_EXPOSE_EPOCH);
             module->p2p_lock_status = 0;
         }
     }
@@ -589,6 +594,7 @@ ompi_osc_pt2pt_passive_unlock(ompi_osc_pt2pt_module_t *module,
     if (NULL != new_pending) {
         opal_output_verbose(50, ompi_osc_base_output,
                             "sending lock request to proc");
+        ompi_win_append_mode(module->p2p_win, OMPI_WIN_EXPOSE_EPOCH);
         /* set lock state and generate a lock request */
         module->p2p_lock_status = new_pending->lock_type;
         ompi_osc_pt2pt_control_send(module,
diff --git a/ompi/mca/osc/rdma/osc_rdma.c b/ompi/mca/osc/rdma/osc_rdma.c
index c43d5118de..eab73f7ea8 100644
--- a/ompi/mca/osc/rdma/osc_rdma.c
+++ b/ompi/mca/osc/rdma/osc_rdma.c
@@ -19,6 +19,7 @@
 #include "osc_rdma.h"
 #include "osc_rdma_sendreq.h"
 
+#include "opal/runtime/opal_progress.h"
 #include "opal/threads/mutex.h"
 #include "ompi/win/win.h"
 #include "ompi/communicator/communicator.h"
@@ -33,6 +34,10 @@ ompi_osc_rdma_module_free(ompi_win_t *win)
     int tmp;
     ompi_osc_rdma_module_t *module = P2P_MODULE(win);
 
+    while (OMPI_WIN_EXPOSE_EPOCH & ompi_win_get_mode(win)) {
+        opal_progress();
+    }
+
     /* finish with a barrier */
     if (ompi_group_size(win->w_group) > 1) {
         ret = module->p2p_comm->c_coll.coll_barrier(module->p2p_comm);
diff --git a/ompi/mca/osc/rdma/osc_rdma_sync.c b/ompi/mca/osc/rdma/osc_rdma_sync.c
index dc2a773d50..540adb39be 100644
--- a/ompi/mca/osc/rdma/osc_rdma_sync.c
+++ b/ompi/mca/osc/rdma/osc_rdma_sync.c
@@ -460,7 +460,8 @@ ompi_osc_rdma_module_lock(int lock_type,
     assert(lock_type != 0);
 
     /* set our mode on the window */
-    ompi_win_set_mode(win, OMPI_WIN_ACCESS_EPOCH | OMPI_WIN_LOCK_ACCESS);
+    ompi_win_remove_mode(win, OMPI_WIN_FENCE);
+    ompi_win_append_mode(win, OMPI_WIN_ACCESS_EPOCH | OMPI_WIN_LOCK_ACCESS);
 
     opal_output_verbose(50, ompi_osc_base_output,
                         "%d sending lock request to %d", 
@@ -531,7 +532,7 @@ ompi_osc_rdma_module_unlock(int target,
                                 out_count);
 
     /* set our mode on the window */
-    ompi_win_set_mode(win, 0);
+    ompi_win_remove_mode(win, OMPI_WIN_ACCESS_EPOCH | OMPI_WIN_LOCK_ACCESS);
 
     return OMPI_SUCCESS;
 }
@@ -551,6 +552,7 @@ ompi_osc_rdma_passive_lock(ompi_osc_rdma_module_t *module,
     if (lock_type == MPI_LOCK_EXCLUSIVE) {
         if (module->p2p_lock_status == 0) {
             module->p2p_lock_status = MPI_LOCK_EXCLUSIVE;
+            ompi_win_append_mode(module->p2p_win, OMPI_WIN_EXPOSE_EPOCH);
             send_ack = true;
         } else {
             opal_output_verbose(50, ompi_osc_base_output,
@@ -565,6 +567,7 @@ ompi_osc_rdma_passive_lock(ompi_osc_rdma_module_t *module,
         if (module->p2p_lock_status != MPI_LOCK_EXCLUSIVE) {
             module->p2p_lock_status = MPI_LOCK_SHARED;
             module->p2p_shared_count++;
+            ompi_win_append_mode(module->p2p_win, OMPI_WIN_EXPOSE_EPOCH);
             send_ack = true;
         } else {
             opal_output_verbose(50, ompi_osc_base_output,
@@ -611,10 +614,12 @@ ompi_osc_rdma_passive_unlock(ompi_osc_rdma_module_t *module,
 
     OPAL_THREAD_LOCK(&(module->p2p_lock));
     if (module->p2p_lock_status == MPI_LOCK_EXCLUSIVE) {
+        ompi_win_remove_mode(module->p2p_win, OMPI_WIN_EXPOSE_EPOCH);
         module->p2p_lock_status = 0;
     } else {
         module->p2p_shared_count--;
         if (module->p2p_shared_count == 0) {
+            ompi_win_remove_mode(module->p2p_win, OMPI_WIN_EXPOSE_EPOCH);
             module->p2p_lock_status = 0;
         }
     }
@@ -627,6 +632,7 @@ ompi_osc_rdma_passive_unlock(ompi_osc_rdma_module_t *module,
     if (NULL != new_pending) {
         opal_output_verbose(50, ompi_osc_base_output,
                             "sending lock request to proc");
+        ompi_win_append_mode(module->p2p_win, OMPI_WIN_EXPOSE_EPOCH);
         /* set lock state and generate a lock request */
         module->p2p_lock_status = new_pending->lock_type;
         ompi_osc_rdma_control_send(module,
diff --git a/ompi/mpi/c/win_free.c b/ompi/mpi/c/win_free.c
index b92bf90dc7..0462296e21 100644
--- a/ompi/mpi/c/win_free.c
+++ b/ompi/mpi/c/win_free.c
@@ -41,8 +41,7 @@ int MPI_Win_free(MPI_Win *win)
 
         if (ompi_win_invalid(*win)) {
             return OMPI_ERRHANDLER_INVOKE(MPI_COMM_WORLD, MPI_ERR_WIN, FUNC_NAME);
-        } else if ((OMPI_WIN_ACCESS_EPOCH|OMPI_WIN_EXPOSE_EPOCH) &
-                   ompi_win_get_mode(*win)) {
+        } else if (OMPI_WIN_ACCESS_EPOCH & ompi_win_get_mode(*win)) {
             return OMPI_ERRHANDLER_INVOKE(*win, 
                                           MPI_ERR_RMA_SYNC, 
                                           FUNC_NAME);