diff --git a/src/db/db/dbNetlistDeviceExtractor.cc b/src/db/db/dbNetlistDeviceExtractor.cc
index 6e4bc6ae2..00cbe62a5 100644
--- a/src/db/db/dbNetlistDeviceExtractor.cc
+++ b/src/db/db/dbNetlistDeviceExtractor.cc
@@ -287,19 +287,37 @@ void NetlistDeviceExtractor::extract_without_initialize (db::Layout &layout, db:
       extractor_cache_type::const_iterator ec = extractor_cache.find (layer_geometry);
       if (ec == extractor_cache.end ()) {
 
+        log_entry_list log_entries;
+        m_log_entries.swap (log_entries);
+
         //  do the actual device extraction
         extract_devices (layer_geometry);
 
         //  push the new devices to the layout
         push_new_devices (disp);
 
-        ExtractorCacheValueType &ecv = extractor_cache [layer_geometry];
-        ecv.disp = disp;
+        if (m_log_entries.empty ()) {
+
+          //  cache unless log entries are produced
+          ExtractorCacheValueType &ecv = extractor_cache [layer_geometry];
+          ecv.disp = disp;
+
+          for (std::map<size_t, std::pair<db::Device *, geometry_per_terminal_type> >::const_iterator d = m_new_devices.begin (); d != m_new_devices.end (); ++d) {
+            ecv.devices.push_back (d->second.first);
+          }
+
+        } else {
+
+          //  transform the marker geometries from the log entries to match the device
+          db::DVector disp_dbu = db::CplxTrans (dbu ()) * disp;
+          for (auto l = m_log_entries.begin (); l != m_log_entries.end (); ++l) {
+            l->set_geometry (l->geometry ().moved (disp_dbu));
+          }
 
-        for (std::map<size_t, std::pair<db::Device *, geometry_per_terminal_type> >::const_iterator d = m_new_devices.begin (); d != m_new_devices.end (); ++d) {
-          ecv.devices.push_back (d->second.first);
         }
 
+        m_log_entries.splice (m_log_entries.begin (), log_entries);
+
         m_new_devices.clear ();
 
       } else {
diff --git a/src/layui/layui/layBrowser.cc b/src/layui/layui/layBrowser.cc
index e47e56525..edfbf4a26 100644
--- a/src/layui/layui/layBrowser.cc
+++ b/src/layui/layui/layBrowser.cc
@@ -95,6 +95,16 @@ Browser::accept ()
   }
 }
 
+void
+Browser::reject ()
+{
+  if (active ()) {
+    m_active = false;
+    deactivated ();
+    QDialog::reject ();
+  }
+}
+
 }
 
 #endif
diff --git a/src/layui/layui/layBrowser.h b/src/layui/layui/layBrowser.h
index 03416ce20..30edb4199 100644
--- a/src/layui/layui/layBrowser.h
+++ b/src/layui/layui/layBrowser.h
@@ -138,6 +138,7 @@ private:
 
   void closeEvent (QCloseEvent *);
   void accept ();
+  void reject ();
 };
 
 }
diff --git a/src/lvs/unit_tests/lvsSimpleTests.cc b/src/lvs/unit_tests/lvsSimpleTests.cc
index cde9e8f7f..d82d5d56d 100644
--- a/src/lvs/unit_tests/lvsSimpleTests.cc
+++ b/src/lvs/unit_tests/lvsSimpleTests.cc
@@ -28,7 +28,7 @@
 #include "lymMacro.h"
 #include "tlFileUtils.h"
 
-void run_test (tl::TestBase *_this, const std::string &suffix, const std::string &layout, bool with_l2n = false, const std::string &top = std::string (), bool change_case = false)
+void run_test (tl::TestBase *_this, const std::string &suffix, const std::string &layout, bool with_l2n = false, bool with_lvs = true, const std::string &top = std::string (), bool change_case = false)
 {
   std::string rs = tl::testdata ();
   rs += "/lvs/" + suffix + ".lvs";
@@ -70,7 +70,9 @@ void run_test (tl::TestBase *_this, const std::string &suffix, const std::string
   lvs.load_from (rs);
   EXPECT_EQ (lvs.run (), 0);
 
-  _this->compare_text_files (output_lvsdb, au_lvsdb);
+  if (with_lvs) {
+    _this->compare_text_files (output_lvsdb, au_lvsdb);
+  }
   _this->compare_text_files (output_cir, au_cir);
   if (with_l2n) {
     _this->compare_text_files (output_l2n, au_l2n);
@@ -121,14 +123,14 @@ TEST(6_simple_pin_swapping)
 {
   run_test (_this, "ringo_simple_pin_swapping", "ringo.gds");
   //  change case
-  run_test (_this, "ringo_simple_pin_swapping", "ringo.gds", false, std::string (), true);
+  run_test (_this, "ringo_simple_pin_swapping", "ringo.gds", false, true, std::string (), true);
 }
 
 TEST(7_net_and_circuit_equivalence)
 {
   run_test (_this, "ringo_simple_net_and_circuit_equivalence", "ringo_renamed.gds");
   //  change case
-  run_test (_this, "ringo_simple_net_and_circuit_equivalence", "ringo_renamed.gds", false, std::string (), true);
+  run_test (_this, "ringo_simple_net_and_circuit_equivalence", "ringo_renamed.gds", false, true, std::string (), true);
 }
 
 TEST(8_simplification)
@@ -166,7 +168,7 @@ TEST(13_simple_ringo_device_subcircuits)
 {
   run_test (_this, "ringo_device_subcircuits", "ringo.gds");
   //  change case
-  run_test (_this, "ringo_device_subcircuits", "ringo.gds", false, std::string (), true);
+  run_test (_this, "ringo_device_subcircuits", "ringo.gds", false, true, std::string (), true);
 }
 
 TEST(14_simple_ringo_mixed_hierarchy)
@@ -181,7 +183,7 @@ TEST(15_simple_dummy_device)
 
 TEST(16_floating)
 {
-  run_test (_this, "floating", "floating.gds", false, "TOP");
+  run_test (_this, "floating", "floating.gds", false, true, "TOP");
 }
 
 TEST(17_layout_variants)
@@ -287,3 +289,9 @@ TEST(31_MustConnect2)
   run_test (_this, "must_connect2", "must_connect2.gds");
 }
 
+//  issue 1609
+TEST(40_DeviceExtractorErrors)
+{
+  run_test (_this, "custom_resistors", "custom_resistors.gds", true, false /*no LVS*/);
+}
+
diff --git a/src/lvs/unit_tests/lvsTests.cc b/src/lvs/unit_tests/lvsTests.cc
index 40de5d859..616b561e2 100644
--- a/src/lvs/unit_tests/lvsTests.cc
+++ b/src/lvs/unit_tests/lvsTests.cc
@@ -165,7 +165,7 @@ TEST(20_private)
 
 TEST(21_private)
 {
-  run_test (_this, "test_21.lylvs", "test_21.cir.gz", "test_21.gds.gz", true, "test_21_3.lvsdb");
+  run_test (_this, "test_21.lylvs", "test_21.cir.gz", "test_21.gds.gz", true, "test_21_4.lvsdb");
 }
 
 //  issue #1021
diff --git a/testdata/lvs/custom_resistors.cir b/testdata/lvs/custom_resistors.cir
new file mode 100644
index 000000000..f49736e76
--- /dev/null
+++ b/testdata/lvs/custom_resistors.cir
@@ -0,0 +1,18 @@
+
+* cell TOP
+.SUBCKT TOP
+* cell instance $1 r180 *1 2,2.6
+X$1 6 1 A
+* cell instance $2 r0 *1 2.2,1
+X$2 6 5 A
+* device instance $1 r0 *1 0.8,0.75 RPP1
+R$1 2 1 0.555555555556 RPP1
+.ENDS TOP
+
+* cell A
+* pin 
+* pin 
+.SUBCKT A 1 2
+* device instance $1 r0 *1 -0.2,0.4 RPP1
+R$1 1 2 1.25 RPP1
+.ENDS A
diff --git a/testdata/lvs/custom_resistors.gds b/testdata/lvs/custom_resistors.gds
new file mode 100644
index 000000000..df4b2d400
Binary files /dev/null and b/testdata/lvs/custom_resistors.gds differ
diff --git a/testdata/lvs/custom_resistors.l2n.1 b/testdata/lvs/custom_resistors.l2n.1
new file mode 100644
index 000000000..1047b4c0a
--- /dev/null
+++ b/testdata/lvs/custom_resistors.l2n.1
@@ -0,0 +1,103 @@
+#%l2n-klayout
+W(TOP)
+U(0.001)
+L(l4 '15/0')
+L(l3 '16/0')
+L(l1)
+C(l4 l4 l3 l1)
+C(l3 l4 l3)
+C(l1 l4 l1)
+H(E B('Resistor shape does not touch marker border in exactly two places') C(TOP) X('device-extract') Q('(0.8,0.75;0.8,1.15;1,1.15;1,0.75)'))
+H(E B('Resistor shape does not touch marker border in exactly two places') C(TOP) X('device-extract') Q('(0,0.75;0,1.15;0.2,1.15;0.2,0.75)'))
+H(E B('Resistor shape does not touch marker border in exactly two places') C(A) X('device-extract') Q('(0.85,-0.4;0.85,-0.2;1.25,-0.2;1.25,-0.4)'))
+K(RPP1 RES)
+D(D$RPP1 RPP1
+ T(A
+  R(l1 (0 400) (200 300))
+ )
+ T(B
+  R(l1 (0 1200) (200 250))
+ )
+)
+D(D$RPP1$1 RPP1
+ T(A
+  R(l1 (0 0) (250 200))
+ )
+ T(B
+  R(l1 (750 0) (250 200))
+ )
+)
+X(A
+ R((-200 -450) (1750 1350))
+ N(1
+  R(l4 (-150 450) (100 100))
+  R(l3 (-150 -150) (200 500))
+  R(l1 (-200 -500) (250 200))
+ )
+ N(2
+  R(l4 (650 450) (100 100))
+  R(l4 (-100 -900) (100 100))
+  R(l3 (-150 200) (200 650))
+  R(l3 (-200 -1000) (200 500))
+  R(l1 (-250 300) (250 200))
+  R(l1 (-200 -1000) (250 200))
+ )
+ N(3
+  R(l4 (1450 -350) (100 100))
+ )
+ P(1)
+ P(2)
+ D(1 D$RPP1$1
+  Y(-200 400)
+  E(R 1.25)
+  E(L 0.5)
+  E(W 0.2)
+  E(A 0.1)
+  E(P 1.4)
+  T(A 1)
+  T(B 2)
+ )
+)
+X(TOP
+ R((-50 450) (3800 2600))
+ N(1
+  R(l4 (850 2050) (100 100))
+  R(l3 (-150 -150) (500 200))
+  R(l1 (-500 -250) (200 250))
+ )
+ N(2
+  R(l4 (850 1250) (100 100))
+  R(l4 (-100 -100) (100 100))
+  R(l4 (-900 -100) (100 100))
+  R(l3 (200 -150) (650 200))
+  R(l3 (-1000 -200) (500 200))
+  R(l1 (300 -250) (200 300))
+  R(l1 (-1000 -300) (200 250))
+ )
+ N(3
+  R(l4 (50 450) (100 100))
+ )
+ N(4
+  R(l4 (850 450) (100 100))
+ )
+ N(5)
+ N(6)
+ D(1 D$RPP1
+  Y(800 750)
+  E(R 0.555555555556)
+  E(L 0.333333333333)
+  E(W 0.3)
+  E(A 0.1)
+  E(P 1.26666666667)
+  T(A 2)
+  T(B 1)
+ )
+ X(1 A O(180) Y(2000 2600)
+  P(0 6)
+  P(1 1)
+ )
+ X(2 A Y(2200 1000)
+  P(0 6)
+  P(1 5)
+ )
+)
diff --git a/testdata/lvs/custom_resistors.l2n.2 b/testdata/lvs/custom_resistors.l2n.2
new file mode 100644
index 000000000..17deb7617
--- /dev/null
+++ b/testdata/lvs/custom_resistors.l2n.2
@@ -0,0 +1,103 @@
+#%l2n-klayout
+W(TOP)
+U(0.001)
+L(l4 '15/0')
+L(l3 '16/0')
+L(l1)
+C(l4 l4 l3 l1)
+C(l3 l4 l3)
+C(l1 l4 l1)
+H(E B('Resistor shape does not touch marker border in exactly two places') C(TOP) X('device-extract') Q('(0,0.75;0,1.15;0.2,1.15;0.2,0.75)'))
+H(E B('Resistor shape does not touch marker border in exactly two places') C(TOP) X('device-extract') Q('(0.8,0.75;0.8,1.15;1,1.15;1,0.75)'))
+H(E B('Resistor shape does not touch marker border in exactly two places') C(A) X('device-extract') Q('(0.85,-0.4;0.85,-0.2;1.25,-0.2;1.25,-0.4)'))
+K(RPP1 RES)
+D(D$RPP1 RPP1
+ T(A
+  R(l1 (0 400) (200 300))
+ )
+ T(B
+  R(l1 (0 1200) (200 250))
+ )
+)
+D(D$RPP1$1 RPP1
+ T(A
+  R(l1 (0 0) (250 200))
+ )
+ T(B
+  R(l1 (750 0) (250 200))
+ )
+)
+X(A
+ R((-200 -450) (1750 1350))
+ N(1
+  R(l4 (-150 450) (100 100))
+  R(l3 (-150 -150) (200 500))
+  R(l1 (-200 -500) (250 200))
+ )
+ N(2
+  R(l4 (650 450) (100 100))
+  R(l4 (-100 -900) (100 100))
+  R(l3 (-150 200) (200 650))
+  R(l3 (-200 -1000) (200 500))
+  R(l1 (-250 300) (250 200))
+  R(l1 (-200 -1000) (250 200))
+ )
+ N(3
+  R(l4 (1450 -350) (100 100))
+ )
+ P(1)
+ P(2)
+ D(1 D$RPP1$1
+  Y(-200 400)
+  E(R 1.25)
+  E(L 0.5)
+  E(W 0.2)
+  E(A 0.1)
+  E(P 1.4)
+  T(A 1)
+  T(B 2)
+ )
+)
+X(TOP
+ R((-50 450) (3800 2600))
+ N(1
+  R(l4 (850 2050) (100 100))
+  R(l3 (-150 -150) (500 200))
+  R(l1 (-500 -250) (200 250))
+ )
+ N(2
+  R(l4 (850 1250) (100 100))
+  R(l4 (-100 -100) (100 100))
+  R(l4 (-900 -100) (100 100))
+  R(l3 (200 -150) (650 200))
+  R(l3 (-1000 -200) (500 200))
+  R(l1 (300 -250) (200 300))
+  R(l1 (-1000 -300) (200 250))
+ )
+ N(3
+  R(l4 (50 450) (100 100))
+ )
+ N(4
+  R(l4 (850 450) (100 100))
+ )
+ N(5)
+ N(6)
+ D(1 D$RPP1
+  Y(800 750)
+  E(R 0.555555555556)
+  E(L 0.333333333333)
+  E(W 0.3)
+  E(A 0.1)
+  E(P 1.26666666667)
+  T(A 2)
+  T(B 1)
+ )
+ X(1 A O(180) Y(2000 2600)
+  P(0 6)
+  P(1 1)
+ )
+ X(2 A Y(2200 1000)
+  P(0 6)
+  P(1 5)
+ )
+)
diff --git a/testdata/lvs/custom_resistors.lvs b/testdata/lvs/custom_resistors.lvs
new file mode 100644
index 000000000..78072f645
--- /dev/null
+++ b/testdata/lvs/custom_resistors.lvs
@@ -0,0 +1,86 @@
+
+source($lvs_test_source, "TOP")
+
+report_netlist($lvs_test_target_l2n)
+target_netlist($lvs_test_target_cir)
+
+deep
+
+# -------------------------------------------------------------------
+# Layers
+
+poly_dg     = input(13, 0)
+cont        = input(15, 0)
+met1_dg     = input(16, 0)
+sblk        = input(34, 0)
+rp_1        = sblk & poly_dg
+p1trm       = poly_dg - rp_1 
+
+class ResistorExtractor < RBA::GenericDeviceExtractor
+
+  def initialize(name, sheet_rho)
+    self.name = name
+    @sheet_rho = sheet_rho
+  end
+
+  def setup
+    define_layer("C", "Conductor")
+    define_layer("R", "Resistor")
+    register_device_class(RBA::DeviceClassResistor::new)
+  end
+
+  def get_connectivity(layout, layers)
+    # this "connectivity" forms the shape clusters that make up the device
+    conn = RBA::Connectivity::new
+    conn.connect(layers[0], layers[1])   # collect touching contacts
+    conn.connect(layers[1], layers[1])   # combine resistor shapes into one area
+    conn
+  end
+  
+  def extract_devices(layer_geometry)
+    # layer_geometry provides the input layers in the order they are defined with "define_layer"
+    conductor = layer_geometry[0]
+    resistor  = layer_geometry[1]
+    
+    resistor_regions = resistor.merged
+
+    resistor_regions.each do |r|
+      terminals = conductor.interacting(RBA::Region::new(r))
+      if terminals.size != 2
+        error("Resistor shape does not touch marker border in exactly two places", r)
+      else
+        double_width = 0
+        (terminals.edges & resistor.edges).merged.each do |e|
+          double_width += e.length
+        end
+        # A = L*W
+        # -> L = A/W
+        a = r.area*dbu*dbu
+        w = (double_width / 2.0)*dbu
+        l = a / w
+
+        device = create_device
+        device.set_parameter(RBA::DeviceClassResistor::PARAM_R, @sheet_rho * l / w);
+        
+        device.set_parameter(RBA::DeviceClassResistor::PARAM_A, a)
+        device.set_parameter(RBA::DeviceClassResistor::PARAM_L, l)
+        device.set_parameter(RBA::DeviceClassResistor::PARAM_P, 2*l+2*w)
+        device.set_parameter(RBA::DeviceClassResistor::PARAM_W, w)
+        define_terminal(device, "A", "C", terminals[0]);
+        define_terminal(device, "B", "C", terminals[1]);
+      end
+    end
+  end
+end
+
+extract_devices(ResistorExtractor::new("RPP1", 0.5), # intentionally wrong: 1565.15/5
+  { "C" => p1trm, "R" => rp_1 })
+
+connect(met1_dg,      cont)
+connect(p1trm,        cont)
+
+begin 
+  netlist
+rescue => ex
+end
+