diff --git a/dcalc/GraphDelayCalc.cc b/dcalc/GraphDelayCalc.cc
index 34fd5c93..9722c76d 100644
--- a/dcalc/GraphDelayCalc.cc
+++ b/dcalc/GraphDelayCalc.cc
@@ -610,7 +610,7 @@ GraphDelayCalc::enqueueTimingChecksEdges(Vertex *vertex)
 {
   if (vertex->hasChecks()) {
     VertexInEdgeIterator edge_iter(vertex, graph_);
-    UniqueLock lock(invalid_edge_lock_);
+    LockGuard lock(invalid_edge_lock_);
     while (edge_iter.hasNext()) {
       Edge *edge = edge_iter.next();
       if (edge->role()->isTimingCheck())
@@ -619,7 +619,7 @@ GraphDelayCalc::enqueueTimingChecksEdges(Vertex *vertex)
   }
   if (vertex->isCheckClk()) {
     VertexOutEdgeIterator edge_iter(vertex, graph_);
-    UniqueLock lock(invalid_edge_lock_);
+    LockGuard lock(invalid_edge_lock_);
     while (edge_iter.hasNext()) {
       Edge *edge = edge_iter.next();
       if (edge->role()->isTimingCheck())
@@ -630,7 +630,7 @@ GraphDelayCalc::enqueueTimingChecksEdges(Vertex *vertex)
     // Latch D->Q arcs have to be re-evaled if level(D) > level(E)
     // because levelization does not traverse D->Q arcs to break loops.
     VertexOutEdgeIterator edge_iter(vertex, graph_);
-    UniqueLock lock(invalid_edge_lock_);
+    LockGuard lock(invalid_edge_lock_);
     while (edge_iter.hasNext()) {
       Edge *edge = edge_iter.next();
       if (edge->role() == TimingRole::latchDtoQ())
@@ -661,7 +661,7 @@ GraphDelayCalc::findMultiDrvrNet(Vertex *drvr_vertex)
 {
   // Avoid locking for single driver nets.
   if (hasMultiDrvrs(drvr_vertex)) {
-    UniqueLock lock(multi_drvr_lock_);
+    LockGuard lock(multi_drvr_lock_);
     MultiDrvrNet *multi_drvr = multiDrvrNet(drvr_vertex);
     if (multi_drvr)
       return multi_drvr;
diff --git a/graph/Graph.cc b/graph/Graph.cc
index 591a2271..2e21e0a4 100644
--- a/graph/Graph.cc
+++ b/graph/Graph.cc
@@ -576,7 +576,7 @@ Graph::makeArrivals(Vertex *vertex,
   Arrival *arrivals;
   ArrivalId id;
   {
-    UniqueLock lock(arrivals_lock_);
+    LockGuard lock(arrivals_lock_);
     arrivals_.make(count, arrivals, id);
   }
   vertex->setArrivals(id);
@@ -594,7 +594,7 @@ Graph::deleteArrivals(Vertex *vertex,
                       uint32_t count)
 {
   {
-    UniqueLock lock(arrivals_lock_);
+    LockGuard lock(arrivals_lock_);
     arrivals_.destroy(vertex->arrivals(), count);
   }
   vertex->setArrivals(arrival_null);
@@ -609,7 +609,7 @@ Graph::makeRequireds(Vertex *vertex,
   Required *requireds;
   ArrivalId id;
   {
-    UniqueLock lock(requireds_lock_);
+    LockGuard lock(requireds_lock_);
     requireds_.make(count, requireds, id);
   }
   vertex->setRequireds(id);
@@ -627,7 +627,7 @@ Graph::deleteRequireds(Vertex *vertex,
                        uint32_t count)
 {
   {
-    UniqueLock lock(requireds_lock_);
+    LockGuard lock(requireds_lock_);
     requireds_.destroy(vertex->requireds(), count);
   }
   vertex->setRequireds(arrival_null);
@@ -647,7 +647,7 @@ Graph::makePrevPaths(Vertex *vertex,
   PathVertexRep *prev_paths;
   PrevPathId id;
   {
-    UniqueLock lock(prev_paths_lock_);
+    LockGuard lock(prev_paths_lock_);
     prev_paths_.make(count, prev_paths, id);
   }
   vertex->setPrevPaths(id);
diff --git a/include/sta/Mutex.hh b/include/sta/Mutex.hh
index fa98d5a0..0e3f5a47 100644
--- a/include/sta/Mutex.hh
+++ b/include/sta/Mutex.hh
@@ -20,6 +20,7 @@
 
 namespace sta {
 
-typedef std::unique_lock<std::mutex> UniqueLock;
+// Hide a bit of the std verbosity.
+typedef std::lock_guard<std::mutex> LockGuard;
 
 } // namespace
diff --git a/parasitics/ConcreteParasitics.cc b/parasitics/ConcreteParasitics.cc
index 37a8d707..f29af721 100644
--- a/parasitics/ConcreteParasitics.cc
+++ b/parasitics/ConcreteParasitics.cc
@@ -920,7 +920,7 @@ ConcreteParasitics::deleteReducedParasitics(const Pin *pin)
 void
 ConcreteParasitics::deleteDrvrReducedParasitics(const Pin *drvr_pin)
 {
-  UniqueLock lock(lock_);
+  LockGuard lock(lock_);
   ConcreteParasitic **parasitics = drvr_parasitic_map_[drvr_pin];
   if (parasitics) {
     int ap_count = corners_->parasiticAnalysisPtCount();
@@ -936,7 +936,7 @@ void
 ConcreteParasitics::deleteDrvrReducedParasitics(const Pin *drvr_pin,
                                                 const ParasiticAnalysisPt *ap)
 {
-  UniqueLock lock(lock_);
+  LockGuard lock(lock_);
   ConcreteParasitic **parasitics = drvr_parasitic_map_[drvr_pin];
   if (parasitics) {
     int ap_index = ap->index();
@@ -961,7 +961,7 @@ ConcreteParasitics::findPiElmore(const Pin *drvr_pin,
 {
   if (!drvr_parasitic_map_.empty()) {
     int ap_rf_index = parasiticAnalysisPtIndex(ap, rf);
-    UniqueLock lock(lock_);
+    LockGuard lock(lock_);
     ConcreteParasitic **parasitics = drvr_parasitic_map_.findKey(drvr_pin);
     if (parasitics) {
       ConcreteParasitic *parasitic = parasitics[ap_rf_index];
@@ -980,7 +980,7 @@ ConcreteParasitics::makePiElmore(const Pin *drvr_pin,
 				 float rpi,
 				 float c1)
 {
-  UniqueLock lock(lock_);
+  LockGuard lock(lock_);
   ConcreteParasitic **parasitics = drvr_parasitic_map_.findKey(drvr_pin);
   if (parasitics == nullptr) {
     int ap_count = corners_->parasiticAnalysisPtCount();
@@ -1077,7 +1077,7 @@ ConcreteParasitics::findPiPoleResidue(const Pin *drvr_pin,
 {
   if (!drvr_parasitic_map_.empty()) {
     int ap_rf_index = parasiticAnalysisPtIndex(ap, rf);
-    UniqueLock lock(lock_);
+    LockGuard lock(lock_);
     ConcreteParasitic **parasitics = drvr_parasitic_map_.findKey(drvr_pin);
     if (parasitics) {
       ConcreteParasitic *parasitic = parasitics[ap_rf_index];
@@ -1100,7 +1100,7 @@ ConcreteParasitics::makePiPoleResidue(const Pin *drvr_pin,
 				      float rpi,
 				      float c1)
 {
-  UniqueLock lock(lock_);
+  LockGuard lock(lock_);
   ConcreteParasitic **parasitics = drvr_parasitic_map_.findKey(drvr_pin);
   if (parasitics == nullptr) {
     int ap_count = corners_->parasiticAnalysisPtCount();
@@ -1194,7 +1194,7 @@ ConcreteParasitics::findParasiticNetwork(const Net *net,
 					 const ParasiticAnalysisPt *ap) const
 {
   if (!parasitic_network_map_.empty()) {
-    UniqueLock lock(lock_);
+    LockGuard lock(lock_);
     if (!parasitic_network_map_.empty()) {
       ConcreteParasiticNetwork **parasitics=parasitic_network_map_.findKey(net);
       if (parasitics) {
@@ -1213,7 +1213,7 @@ ConcreteParasitics::findParasiticNetwork(const Pin *pin,
 					 const ParasiticAnalysisPt *ap) const
 {
   if (!parasitic_network_map_.empty()) {
-    UniqueLock lock(lock_);
+    LockGuard lock(lock_);
     if (!parasitic_network_map_.empty()) {
       // Only call findParasiticNet if parasitics exist.
       const Net *net = findParasiticNet(pin);
@@ -1234,7 +1234,7 @@ ConcreteParasitics::makeParasiticNetwork(const Net *net,
 					 bool includes_pin_caps,
 					 const ParasiticAnalysisPt *ap)
 {
-  UniqueLock lock(lock_);
+  LockGuard lock(lock_);
   ConcreteParasiticNetwork **parasitics = parasitic_network_map_.findKey(net);
   if (parasitics == nullptr) {
     int ap_count = corners_->parasiticAnalysisPtCount();
@@ -1260,7 +1260,7 @@ ConcreteParasitics::deleteParasiticNetwork(const Net *net,
 					   const ParasiticAnalysisPt *ap)
 {
   if (!parasitic_network_map_.empty()) {
-    UniqueLock lock(lock_);
+    LockGuard lock(lock_);
     ConcreteParasiticNetwork **parasitics = parasitic_network_map_.findKey(net);
     if (parasitics) {
       int ap_index = ap->index();
@@ -1287,7 +1287,7 @@ void
 ConcreteParasitics::deleteParasiticNetworks(const Net *net)
 {
   if (!parasitic_network_map_.empty()) {
-    UniqueLock lock(lock_);
+    LockGuard lock(lock_);
     ConcreteParasiticNetwork **parasitics = parasitic_network_map_.findKey(net);
     if (parasitics) {
       int ap_count = corners_->parasiticAnalysisPtCount();
diff --git a/sdc/Sdc.cc b/sdc/Sdc.cc
index bbf0106e..b063a8c4 100644
--- a/sdc/Sdc.cc
+++ b/sdc/Sdc.cc
@@ -2338,7 +2338,7 @@ CycleAccting *
 Sdc::cycleAccting(const ClockEdge *src,
 		  const ClockEdge *tgt)
 {
-  UniqueLock lock(cycle_acctings_lock_);
+  LockGuard lock(cycle_acctings_lock_);
   return cycle_acctings_.cycleAccting(src, tgt);
 }
 
diff --git a/search/Bfs.cc b/search/Bfs.cc
index bc77bb4e..95f0c0e7 100644
--- a/search/Bfs.cc
+++ b/search/Bfs.cc
@@ -256,7 +256,7 @@ BfsIterator::enqueue(Vertex *vertex)
   debugPrint(debug_, "bfs", 2, "enqueue %s", vertex->name(sdc_network_));
   if (!vertex->bfsInQueue(bfs_index_)) {
     Level level = vertex->level();
-    UniqueLock lock(queue_lock_);
+    LockGuard lock(queue_lock_);
     if (!vertex->bfsInQueue(bfs_index_)) {
       vertex->setBfsInQueue(bfs_index_, true);
       queue_[level].push_back(vertex);
diff --git a/search/PathGroup.cc b/search/PathGroup.cc
index 8e08d9e4..40d793fe 100644
--- a/search/PathGroup.cc
+++ b/search/PathGroup.cc
@@ -121,7 +121,7 @@ PathGroup::savable(PathEnd *path_end)
 void
 PathGroup::insert(PathEnd *path_end)
 {
-  UniqueLock lock(lock_);
+  LockGuard lock(lock_);
   path_ends_.push_back(path_end);
   if (group_count_ != group_count_max
       && static_cast<int>(path_ends_.size()) > group_count_ * 2)
@@ -190,7 +190,7 @@ PathGroup::sort()
 void
 PathGroup::clear()
 {
-  UniqueLock lock(lock_);
+  LockGuard lock(lock_);
   threshold_ = min_max_->initValue();
   path_ends_.clear();
 }
diff --git a/search/Search.cc b/search/Search.cc
index 7ba2a018..2eefcd4a 100644
--- a/search/Search.cc
+++ b/search/Search.cc
@@ -748,7 +748,7 @@ Search::arrivalInvalid(Vertex *vertex)
                vertex->name(sdc_network_));
     if (!arrival_iter_->inQueue(vertex)) {
       // Lock for StaDelayCalcObserver called by delay calc threads.
-      UniqueLock lock(invalid_arrivals_lock_);
+      LockGuard lock(invalid_arrivals_lock_);
       invalid_arrivals_->insert(vertex);
     }
     tnsInvalid(vertex);
@@ -818,7 +818,7 @@ Search::requiredInvalid(Vertex *vertex)
                vertex->name(sdc_network_));
     if (!required_iter_->inQueue(vertex)) {
       // Lock for StaDelayCalcObserver called by delay calc threads.
-      UniqueLock lock(invalid_arrivals_lock_);
+      LockGuard lock(invalid_arrivals_lock_);
       invalid_requireds_->insert(vertex);
     }
     tnsInvalid(vertex);
@@ -1379,7 +1379,7 @@ Search::enqueueLatchDataOutputs(Vertex *vertex)
     Edge *out_edge = out_edge_iter.next();
     if (latches_->isLatchDtoQ(out_edge)) {
       Vertex *out_vertex = out_edge->to(graph_);
-      UniqueLock lock(pending_latch_outputs_lock_);
+      LockGuard lock(pending_latch_outputs_lock_);
       pending_latch_outputs_->insert(out_vertex);
     }
   }
@@ -2623,7 +2623,7 @@ TagGroup *
 Search::findTagGroup(TagGroupBldr *tag_bldr)
 {
   TagGroup probe(tag_bldr);
-  UniqueLock lock(tag_group_lock_);
+  LockGuard lock(tag_group_lock_);
   TagGroup *tag_group = tag_group_set_->findKey(&probe);
   if (tag_group == nullptr) {
     TagGroupIndex tag_group_index;
@@ -2853,7 +2853,7 @@ Search::findTag(const RiseFall *rf,
 {
   Tag probe(0, rf->index(), path_ap->index(), clk_info, is_clk, input_delay,
 	    is_segment_start, states, false, this);
-  UniqueLock lock(tag_lock_);
+  LockGuard lock(tag_lock_);
   Tag *tag = tag_set_->findKey(&probe);
   if (tag == nullptr) {
     ExceptionStateSet *new_states = !own_states && states
@@ -2944,7 +2944,7 @@ Search::findClkInfo(const ClockEdge *clk_edge,
   ClkInfo probe(clk_edge, clk_src, is_propagated, gen_clk_src, gen_clk_src_path,
 		pulse_clk_sense, insertion, latency, uncertainties,
 		path_ap->index(), crpr_clk_path_rep, this);
-  UniqueLock lock(clk_info_lock_);
+  LockGuard lock(clk_info_lock_);
   ClkInfo *clk_info = clk_info_set_->findKey(&probe);
   if (clk_info == nullptr) {
     clk_info = new ClkInfo(clk_edge, clk_src,
@@ -3718,7 +3718,7 @@ Search::tnsInvalid(Vertex *vertex)
       && isEndpoint(vertex)) {
     debugPrint(debug_, "tns", 2, "tns invalid %s",
                vertex->name(sdc_network_));
-    UniqueLock lock(tns_lock_);
+    LockGuard lock(tns_lock_);
     invalid_tns_->insert(vertex);
   }
 }
diff --git a/search/Sim.cc b/search/Sim.cc
index 105d5d38..6d67611a 100644
--- a/search/Sim.cc
+++ b/search/Sim.cc
@@ -81,7 +81,7 @@ Sim::functionSense(const FuncExpr *expr,
              expr->asString());
   bool increasing, decreasing;
   {
-    UniqueLock lock(bdd_lock_);
+    LockGuard lock(bdd_lock_);
     DdNode *bdd = funcBddSim(expr, inst);
     DdManager *cudd_mgr = bdd_.cuddMgr();
     LibertyPort *input_port = network_->libertyPort(input_pin);
@@ -111,7 +111,7 @@ LogicValue
 Sim::evalExpr(const FuncExpr *expr,
 	      const Instance *inst)
 {
-  UniqueLock lock(bdd_lock_);
+  LockGuard lock(bdd_lock_);
   DdNode *bdd = funcBddSim(expr, inst);
   LogicValue value = LogicValue::unknown;
   DdManager *cudd_mgr = bdd_.cuddMgr();
diff --git a/search/WorstSlack.cc b/search/WorstSlack.cc
index 611096ac..a6dae0d5 100644
--- a/search/WorstSlack.cc
+++ b/search/WorstSlack.cc
@@ -120,7 +120,7 @@ WorstSlack::WorstSlack(const WorstSlack &worst_slack) :
 void
 WorstSlack::deleteVertexBefore(Vertex *vertex)
 {
-  UniqueLock lock(lock_);
+  LockGuard lock(lock_);
   if (vertex == worst_vertex_) {
     worst_vertex_ = nullptr;
     worst_slack_ = slack_init_;
@@ -269,7 +269,7 @@ WorstSlack::updateWorstSlack(Vertex *vertex,
 
   // Locking is required because ArrivalVisitor is called by multiple
   // threads.
-  UniqueLock lock(lock_);
+  LockGuard lock(lock_);
   if (worst_vertex_
       && delayLess(slack, worst_slack_, this))
     setWorstSlack(vertex, slack);
diff --git a/util/StringUtil.cc b/util/StringUtil.cc
index bafd9420..7d67911a 100644
--- a/util/StringUtil.cc
+++ b/util/StringUtil.cc
@@ -191,7 +191,7 @@ getTmpString(// Return values.
 	     char *&str,
 	     size_t &length)
 {
-  UniqueLock lock(string_lock_);
+  LockGuard lock(string_lock_);
   if (tmp_string_next_ == tmp_string_count_)
     tmp_string_next_ = 0;
   str = tmp_strings_[tmp_string_next_];
@@ -202,7 +202,7 @@ getTmpString(// Return values.
 char *
 makeTmpString(size_t length)
 {
-  UniqueLock lock(string_lock_);
+  LockGuard lock(string_lock_);
   if (tmp_string_next_ == tmp_string_count_)
     tmp_string_next_ = 0;
   char *tmp_str = tmp_strings_[tmp_string_next_];