diff --git a/OPTYap/opt.init.c b/OPTYap/opt.init.c
index d7407158d..aee3ab6b3 100644
--- a/OPTYap/opt.init.c
+++ b/OPTYap/opt.init.c
@@ -122,13 +122,11 @@ void Yap_init_global_optyap_data(int max_table_size, int n_workers, int sch_loop
   BITMAP_clear(GLOBAL_bm_root_cp_workers);
   BITMAP_clear(GLOBAL_bm_invisible_workers);
   BITMAP_clear(GLOBAL_bm_requestable_workers);
-  BITMAP_clear(GLOBAL_bm_executing_workers);
   BITMAP_copy(GLOBAL_bm_finished_workers, GLOBAL_bm_present_workers);
   INIT_LOCK(GLOBAL_locks_bm_idle_workers);
   INIT_LOCK(GLOBAL_locks_bm_root_cp_workers);
   INIT_LOCK(GLOBAL_locks_bm_invisible_workers);
   INIT_LOCK(GLOBAL_locks_bm_requestable_workers);
-  INIT_LOCK(GLOBAL_locks_bm_executing_workers);
   INIT_LOCK(GLOBAL_locks_bm_finished_workers);
 #ifdef TABLING_INNER_CUTS
   INIT_LOCK(GLOBAL_locks_bm_pruning_workers);
diff --git a/OPTYap/opt.preds.c b/OPTYap/opt.preds.c
index 25b71a3e5..49520fcdd 100644
--- a/OPTYap/opt.preds.c
+++ b/OPTYap/opt.preds.c
@@ -735,7 +735,6 @@ static Int p_yapor_start( USES_REGS1 ) {
   GLOBAL_parallel_mode = PARALLEL_MODE_RUNNING;
   GLOBAL_execution_time = current_time();
   BITMAP_clear(GLOBAL_bm_finished_workers);
-  PUT_IN_EXECUTING(worker_id);
   return (TRUE);
 }
 
diff --git a/OPTYap/opt.structs.h b/OPTYap/opt.structs.h
index 92d310c1a..566aa4907 100644
--- a/OPTYap/opt.structs.h
+++ b/OPTYap/opt.structs.h
@@ -235,7 +235,6 @@ struct global_optyap_locks {
   lockvar bitmap_root_cp_workers;
   lockvar bitmap_invisible_workers;
   lockvar bitmap_requestable_workers;
-  lockvar bitmap_executing_workers;
   lockvar bitmap_finished_workers;
 #ifdef TABLING_INNER_CUTS
   lockvar bitmap_pruning_workers;
@@ -309,7 +308,6 @@ struct global_optyap_data {
   volatile bitmap root_cp_workers;
   volatile bitmap invisible_workers;
   volatile bitmap requestable_workers;
-  volatile bitmap executing_workers;
   volatile bitmap finished_workers;
 #ifdef TABLING_INNER_CUTS
   volatile bitmap pruning_workers;
@@ -384,14 +382,12 @@ struct global_optyap_data {
 #define GLOBAL_bm_root_cp_workers               (GLOBAL_optyap_data.root_cp_workers)
 #define GLOBAL_bm_invisible_workers             (GLOBAL_optyap_data.invisible_workers)
 #define GLOBAL_bm_requestable_workers           (GLOBAL_optyap_data.requestable_workers)
-#define GLOBAL_bm_executing_workers             (GLOBAL_optyap_data.executing_workers)
 #define GLOBAL_bm_finished_workers              (GLOBAL_optyap_data.finished_workers)
 #define GLOBAL_bm_pruning_workers               (GLOBAL_optyap_data.pruning_workers)
 #define GLOBAL_locks_bm_idle_workers            (GLOBAL_optyap_data.locks.bitmap_idle_workers)
 #define GLOBAL_locks_bm_root_cp_workers         (GLOBAL_optyap_data.locks.bitmap_root_cp_workers)
 #define GLOBAL_locks_bm_invisible_workers       (GLOBAL_optyap_data.locks.bitmap_invisible_workers)
 #define GLOBAL_locks_bm_requestable_workers     (GLOBAL_optyap_data.locks.bitmap_requestable_workers)
-#define GLOBAL_locks_bm_executing_workers       (GLOBAL_optyap_data.locks.bitmap_executing_workers)
 #define GLOBAL_locks_bm_finished_workers        (GLOBAL_optyap_data.locks.bitmap_finished_workers)
 #define GLOBAL_locks_bm_pruning_workers         (GLOBAL_optyap_data.locks.bitmap_pruning_workers)
 #define GLOBAL_locks_who_locked_heap            (GLOBAL_optyap_data.locks.who_locked_heap)
diff --git a/OPTYap/or.copy_engine.c b/OPTYap/or.copy_engine.c
index 037d2f1d9..0fe4c4c12 100644
--- a/OPTYap/or.copy_engine.c
+++ b/OPTYap/or.copy_engine.c
@@ -353,6 +353,7 @@ sync_with_p:
 #endif /* incremental */
 
   /* update registers and return */
+  PUT_OUT_ROOT_NODE(worker_id);
 #ifndef TABLING
   REMOTE_reply_signal(worker_p) = worker_ready;
 #endif /* TABLING */
diff --git a/OPTYap/or.insts.i b/OPTYap/or.insts.i
index e918e75cd..6e3091540 100644
--- a/OPTYap/or.insts.i
+++ b/OPTYap/or.insts.i
@@ -17,22 +17,19 @@
 
   PBOp(getwork_first_time,e)
     /* wait for a new parallel goal */
-    while (BITMAP_same(GLOBAL_bm_present_workers, GLOBAL_bm_finished_workers));
+    while (BITMAP_same(GLOBAL_bm_present_workers,GLOBAL_bm_finished_workers));
     make_root_choice_point();  
-    PUT_IN_EXECUTING(worker_id);
-    /* wait until everyone else is executing! */
-    while (! BITMAP_same(GLOBAL_bm_present_workers, GLOBAL_bm_executing_workers));
     SCHEDULER_GET_WORK();
   shared_end:
     PUT_IN_FINISHED(worker_id);
     /* wait until everyone else is finished! */
-    while (! BITMAP_same(GLOBAL_bm_present_workers, GLOBAL_bm_finished_workers));
-    PUT_OUT_EXECUTING(worker_id);
+    while (! BITMAP_same(GLOBAL_bm_present_workers,GLOBAL_bm_finished_workers));
+    PUT_OUT_ROOT_NODE(worker_id);
     if (worker_id == 0) {
       finish_yapor();
       free_root_choice_point();
       /* wait until no one is executing */
-      while (! BITMAP_empty(GLOBAL_bm_executing_workers));
+      while (! BITMAP_empty(GLOBAL_bm_root_cp_workers));
       goto fail;
     } else {
       PREG = GETWORK_FIRST_TIME;
@@ -43,6 +40,7 @@
 
 
 
+
   PBOp(getwork,Otapl)
 #ifdef TABLING
     if (DepFr_leader_cp(LOCAL_top_dep_fr) == Get_LOCAL_top_cp()) {
diff --git a/OPTYap/or.macros.h b/OPTYap/or.macros.h
index 60fed95d7..8fe15b034 100644
--- a/OPTYap/or.macros.h
+++ b/OPTYap/or.macros.h
@@ -18,8 +18,8 @@
 /* get a def for NULL */
 #include <stdlib.h>
 
-static inline void PUT_IN_EXECUTING(int);
-static inline void PUT_OUT_EXECUTING(int);
+static inline void PUT_IN_ROOT_NODE(int);
+static inline void PUT_OUT_ROOT_NODE(int);
 static inline void PUT_IN_FINISHED(int);
 #ifdef TABLING_INNER_CUTS
 static inline void PUT_IN_PRUNING(int);
@@ -213,25 +213,23 @@ static inline qg_sol_fr_ptr CUT_prune_solution_frames(qg_sol_fr_ptr, int);
 /* ---------------------- **
 **      Engine Stuff      **
 ** ---------------------- */
-
-static inline 
-void PUT_IN_EXECUTING(int w) {
-  LOCK(GLOBAL_locks_bm_executing_workers);
-  BITMAP_insert(GLOBAL_bm_executing_workers, w);
-  UNLOCK(GLOBAL_locks_bm_executing_workers);
+static inline
+void PUT_IN_ROOT_NODE(int worker_num) {
+  LOCK(GLOBAL_locks_bm_root_cp_workers);
+  BITMAP_insert(GLOBAL_bm_root_cp_workers, worker_num);
+  UNLOCK(GLOBAL_locks_bm_root_cp_workers);
   return;
 }
 
 
-static inline 
-void PUT_OUT_EXECUTING(int w) {
-  LOCK(GLOBAL_locks_bm_executing_workers);
-  BITMAP_delete(GLOBAL_bm_executing_workers, w);
-  UNLOCK(GLOBAL_locks_bm_executing_workers);
+static inline
+void PUT_OUT_ROOT_NODE(int worker_num) {
+  LOCK(GLOBAL_locks_bm_root_cp_workers);
+  BITMAP_delete(GLOBAL_bm_root_cp_workers, worker_num);
+  UNLOCK(GLOBAL_locks_bm_root_cp_workers);
   return;
 }
 
-
 static inline 
 void PUT_IN_FINISHED(int w) {
   LOCK(GLOBAL_locks_bm_finished_workers);
diff --git a/OPTYap/or.scheduler.c b/OPTYap/or.scheduler.c
index 023433e1e..4d1302c3f 100644
--- a/OPTYap/or.scheduler.c
+++ b/OPTYap/or.scheduler.c
@@ -45,8 +45,6 @@ static int search_for_hidden_shared_work(bitmap stable_busy);
 static inline void PUT_NO_WORK_IN_UPPER_NODES(void);
 static inline void PUT_IDLE(int);
 static inline void PUT_BUSY(int);
-static inline void PUT_IN_ROOT_NODE(int);
-static inline void PUT_OUT_ROOT_NODE(int);
 static inline void move_up_to_prune_request(void);
 
 
@@ -81,24 +79,6 @@ void PUT_BUSY(int worker_num) {
 }
 
 
-static inline
-void PUT_IN_ROOT_NODE(int worker_num) {
-  LOCK(GLOBAL_locks_bm_root_cp_workers);
-  BITMAP_insert(GLOBAL_bm_root_cp_workers, worker_num);
-  UNLOCK(GLOBAL_locks_bm_root_cp_workers);
-  return;
-}
-
-
-static inline
-void PUT_OUT_ROOT_NODE(int worker_num) {
-  LOCK(GLOBAL_locks_bm_root_cp_workers);
-  BITMAP_delete(GLOBAL_bm_root_cp_workers, worker_num);
-  UNLOCK(GLOBAL_locks_bm_root_cp_workers);
-  return;
-}
-
-
 static inline
 void move_up_to_prune_request(void) {
   CACHE_REGS
@@ -216,7 +196,7 @@ int get_work(void) {
   
   counter = 0;
   BITMAP_difference(stable_busy, OrFr_members(LOCAL_top_or_fr), GLOBAL_bm_idle_workers);
-  while (1) {
+   while (1) {
     while (BITMAP_subset(GLOBAL_bm_idle_workers, OrFr_members(LOCAL_top_or_fr)) &&
            Get_LOCAL_top_cp() != Get_GLOBAL_root_cp()) {
       /* no busy workers here and below */
@@ -227,13 +207,17 @@ int get_work(void) {
     }
     if (Get_LOCAL_top_cp() == Get_GLOBAL_root_cp()) {
       if (! BITMAP_member(GLOBAL_bm_root_cp_workers, worker_id))
+        /* We need this extra bitmap because the GLOBAL_bm_idle_workers bitmap 
+           is not enough to deal with sequential predicates. The condition of
+           all workers being idle is not sufficient to ensure that there is no 
+           available computation since a sequential predicate can still be resumed.
+           Only when all workers are idle and in the root choicepoint it is safe to
+           finish execution. */
         PUT_IN_ROOT_NODE(worker_id);
-      if (BITMAP_same(GLOBAL_bm_idle_workers, GLOBAL_bm_root_cp_workers) &&
-          BITMAP_same(GLOBAL_bm_idle_workers, GLOBAL_bm_present_workers)) {
-        /* All workers are idle in root choicepoint. Execution 
+      if (BITMAP_same(GLOBAL_bm_root_cp_workers, GLOBAL_bm_present_workers))
+        /* All workers are idle in the root choicepoint. Execution 
            must finish as there is no available computation. */
         return FALSE;
-      }
     }
     if (get_work_below()) {
       PUT_BUSY(worker_id);
diff --git a/OPTYap/or.thread_engine.c b/OPTYap/or.thread_engine.c
index e5143e7ea..c9a95574b 100644
--- a/OPTYap/or.thread_engine.c
+++ b/OPTYap/or.thread_engine.c
@@ -216,7 +216,7 @@ int q_share_work(int worker_p) {
   Yap_CopyThreadStacks(worker_id, worker_p, FALSE);
 #endif
 
-
+  PUT_OUT_ROOT_NODE(worker_id);
   /* update registers and return */
 #ifndef TABLING
   REMOTE_reply_signal(worker_p) = worker_ready;