diff --git a/CHANGELOG b/CHANGELOG
index 9f7905b..bb8c470 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,3 +1,10 @@
+studio-controls version 2.3.7
+
+ [ Len Ovens ]
+ - Ensure value exists before using in auto_jack.py
+ - Ensure value exists before using in autojack
+ - Don't read empty lock file
+
 studio-controls version 2.3.6
 
  [ Len Ovens ]
diff --git a/usr/bin/autojack b/usr/bin/autojack
index faca295..5c38b5e 100755
--- a/usr/bin/autojack
+++ b/usr/bin/autojack
@@ -1795,8 +1795,6 @@ def jack_info(mesg):
 def ses_cb_command(*args, **kwargs):
     ''' Generic signal receiver '''
     global control_signal
-    rec_string = f"args: {str(args[0])}"
-    # logging.debug(f"got signal - {rec_string}")
     control_signal = args
 
 
@@ -1807,6 +1805,7 @@ def command_run():
     global phones
     global control_signal
     args = control_signal
+    rec_string = f"args: {str(args[0])}"
     logging.debug(f"got signal - {rec_string}")
     if 'start' in args:
         logging.info("Got start signal.")
@@ -1919,18 +1918,20 @@ def main():
     new_pid = str(os.getpid())
     old_pid = new_pid
     if os.path.isfile(lock_file):
-        # other instance still hasn't gone maybe hung
-        with open(lock_file, "r") as lk_file:
-            for line in lk_file:
-                # only need one line
-                old_pid = line.rstrip()
-        if new_pid != old_pid:
-            print("old lock file found, killing old pid")
-            try:
-                os.kill(int(old_pid), 9)
-            except Exception:
-                print("")
-            time.sleep(1)
+        file_stats = os.stat(lock_file)
+        if int(file_stats.st_size):
+            # other instance still hasn't gone maybe hung
+            with open(lock_file, "r") as lk_file:
+                for line in lk_file:
+                    # only need one line
+                    old_pid = line.rstrip()
+            if new_pid != old_pid:
+                print("old lock file found, killing old pid")
+                try:
+                    os.kill(int(old_pid), 9)
+                except Exception:
+                    print("")
+                time.sleep(1)
     with open(lock_file, "w") as lk_file:
         lk_file.write(new_pid)
         print("Lock file created")
diff --git a/usr/lib/python3/dist-packages/auto_jack.py b/usr/lib/python3/dist-packages/auto_jack.py
index 07eea3e..7606e26 100644
--- a/usr/lib/python3/dist-packages/auto_jack.py
+++ b/usr/lib/python3/dist-packages/auto_jack.py
@@ -581,6 +581,7 @@ def check_devices(our_db):
                 sub_db['description'] = "unknown"
 
     # now find the real number
+    ndevs = -1
     if os.path.exists("/proc/asound/cards"):
         with open("/proc/asound/cards", "r") as cards_file:
             for line in cards_file:
@@ -592,6 +593,8 @@ def check_devices(our_db):
                     ndevs = int(first_el)
     else:
         return our_db
+    if ndevs == -1:
+        return our_db
     ndevs += 1
     for x in range(0, ndevs):
         # card loop
diff --git a/usr/share/studio-controls/version b/usr/share/studio-controls/version
index e75da3e..00355e2 100644
--- a/usr/share/studio-controls/version
+++ b/usr/share/studio-controls/version
@@ -1 +1 @@
-2.3.6
+2.3.7