diff --git a/commonb.c b/commonb.c
index a106ccb..2617414 100644
--- a/commonb.c
+++ b/commonb.c
@@ -1495,20 +1495,13 @@ unsigned long max_mem (
 	return (MAX_MEM);
 }
 
-/* Return memory (in MB) now available for a variable usage thread. */
-/* This routine takes into account the memory used by other workers. */
+/* Can we get "lots of memory", whatever that means? (Rules, slot counts) */
 
-int avail_mem (
-	int	thread_num,
-	unsigned long minimum_memory,	/* If this much memory (in MB) can be returned without restarting other workers, then do so */
-	unsigned long desired_memory,	/* If this much memory (in MB) can be returned without restarting other workers, then do so */
-	unsigned int *memory)		/* Returned available memory, in MB */
+int avail_mem_qualitative (
+	int	thread_num)		/* Returned available memory, in MB */
 {
-	int	i, fixed_threads[MAX_NUM_WORKERS];
-	unsigned long fixed_usage, variable_usage, num_variable_threads, avail, diff;
-
+	int lots_occupied = 0;
 /* Check if we are in a period of forced low memory usage */
-
 	if (is_LowMemWhileRunning_active (thread_num)) {
 		MEM_RESTART_FLAGS[thread_num] |= MEM_RESTART_LOWMEM_ENDS;
 		return (STOP_NOT_ENOUGH_MEM);
@@ -1522,19 +1515,37 @@ int avail_mem (
 		return (STOP_NOT_ENOUGH_MEM);
 	}
 
-/* Obtain lock before accessing memory global variables */
+/* Check if we must wait for more memory to become available.  This happens when we reach the maximum allowable number of threads using a lot of memory. */
 
 	gwmutex_lock (&MEM_MUTEX);
+	lots_occupied = are_threads_using_lots_of_memory (thread_num);
+	gwmutex_unlock (&MEM_MUTEX);
 
-/* Check if we must wait for more memory to become available.  This happens when we reach the maximum allowable number of threads using a lot of memory. */
-
-	if (are_threads_using_lots_of_memory (thread_num)) {
+	if (lots_occupied) {
 		MEM_RESTART_FLAGS[thread_num] |= MEM_RESTART_TOO_MANY_HIGHMEM;
-		gwmutex_unlock (&MEM_MUTEX);
 		OutputStr (thread_num, "Exceeded limit on number of workers that can use lots of memory.\n");
 		return (STOP_NOT_ENOUGH_MEM);
 	}
 
+	return (0);
+}
+
+/* Return memory (in MB) now available for a variable usage thread. */
+/* This routine takes into account the memory used by other workers. */
+
+int avail_mem (
+	int	thread_num,
+	unsigned long minimum_memory,	/* If this much memory (in MB) can be returned without restarting other workers, then do so */
+	unsigned long desired_memory,	/* If this much memory (in MB) can be returned without restarting other workers, then do so */
+	unsigned int *memory)		/* Returned available memory, in MB */
+{
+	int	i, fixed_threads[MAX_NUM_WORKERS];
+	unsigned long fixed_usage, variable_usage, num_variable_threads, avail, diff;
+
+/* Obtain lock before accessing memory global variables */
+
+	gwmutex_lock (&MEM_MUTEX);
+
 /* Set flag saying this will be a variable usage thread.  Remember the */
 /* "good enough" value as it will be helpful in determining the best */
 /* value this routine should return (for this thread and other threads) */
diff --git a/ecm.cpp b/ecm.cpp
index 38ffdbb..b54597e 100644
--- a/ecm.cpp
+++ b/ecm.cpp
@@ -7806,6 +7806,13 @@ replan:	unsigned long best_fftlen;
 	best_fails = 0;
 	best_poly_efficiency = 0.0;
 	msgbuf[0] = 0;
+
+	stop_reason = avail_mem_qualitative(thread_num);
+	if (stop_reason) {
+		if (ecmdata.state == ECM_STATE_MIDSTAGE) ecm_save (&ecmdata);
+		goto exit;
+	}
+
 	for (bool found_best = FALSE; ; ) {
 
 /* Initialize the polymult library (needed for calling polymult_mem_required).  Let user override polymult tuning parameters. */
@@ -12333,6 +12340,13 @@ replan:	unsigned long best_fftlen;
 	best_fails = 0;
 	best_poly_efficiency = 0.0;
 	msgbuf[0] = 0;
+
+	stop_reason = avail_mem_qualitative(thread_num);
+	if (stop_reason) {
+		if (pm1data.state == PM1_STATE_MIDSTAGE) pm1_save (&pm1data);
+		goto exit;
+	}
+
 //GW: Can we get here (old save files) with V set and one of x or invx not set?  If so, switching is an issue unless we convert V to binary.
 	for (bool found_best = FALSE; ; ) {
 
@@ -14918,7 +14932,7 @@ int pp1_stage2_impl (
 	min_memory = 1 + cvt_gwnums_to_mem (&pp1data->gwdata, 8);
 	if (pp1data->state < PP1_STATE_STAGE2) desired_memory = 3 + cvt_gwnums_to_mem (&pp1data->gwdata, 144);
 	else desired_memory = (unsigned int) (pp1data->pairmap_size >> 20) + cvt_gwnums_to_mem (&pp1data->gwdata, pp1data->stage2_numvals);
-	stop_reason = avail_mem (pp1data->thread_num, min_memory, desired_memory, &memory);
+	stop_reason = avail_mem_qualitative (pp1data->thread_num) || avail_mem (pp1data->thread_num, min_memory, desired_memory, &memory);
 	if (stop_reason) return (stop_reason);
 
 /* Factor in the multiplier that we set to less than 1.0 when we get unexpected memory allocation errors. */