diff --git a/xschem_library/devices/simulator_commands.sym b/xschem_library/devices/simulator_commands.sym
index fff29302..f15ca8a0 100644
--- a/xschem_library/devices/simulator_commands.sym
+++ b/xschem_library/devices/simulator_commands.sym
@@ -1,4 +1,4 @@
-v {xschem version=3.4.4 file_version=1.2
+v {xschem version=3.4.5 file_version=1.2
 *
 * This file is part of XSCHEM,
 * a schematic capture and Spice/Vhdl/Verilog netlisting tool for circuit
@@ -29,10 +29,12 @@ value=\\"
 \\""
 
 format="tcleval(
-[if \{[ sim_is_@simulator ]\} \{ return \{
+[if \{[catch \{sim_is_@simulator \} retval] \} \{
+  return \{\} \} elseif \{$retval\} \{ return \{
 \\\\@value
-\}\}]
-)"
+\}
+\} else \{ return \{\} \}
+])"
 }
 V {}
 S {}
diff --git a/xschem_library/devices/simulator_commands_shown.sym b/xschem_library/devices/simulator_commands_shown.sym
index 4b17239f..ca00873a 100644
--- a/xschem_library/devices/simulator_commands_shown.sym
+++ b/xschem_library/devices/simulator_commands_shown.sym
@@ -1,4 +1,4 @@
-v {xschem version=3.4.4 file_version=1.2
+v {xschem version=3.4.5 file_version=1.2
 *
 * This file is part of XSCHEM,
 * a schematic capture and Spice/Vhdl/Verilog netlisting tool for circuit
@@ -29,10 +29,12 @@ value=\\"
 \\""
 
 format="tcleval(
-[if \{[ sim_is_@simulator ]\} \{ return \{
+[if \{[catch \{sim_is_@simulator \} retval] \} \{
+  return \{\} \} elseif \{$retval\} \{ return \{
 \\\\@value
-\}\}]
-)"}
+\}
+\} else \{ return \{\} \}
+])"}
 V {}
 S {}
 E {}