diff --git a/mopidy_iris/system.py b/mopidy_iris/system.py
index 64ee4c74..37b40045 100755
--- a/mopidy_iris/system.py
+++ b/mopidy_iris/system.py
@@ -4,6 +4,27 @@ import logging, pathlib, subprocess, json
 # import logger
 logger = logging.getLogger(__name__)
 
+
+class IrisSystemError(Exception):
+    pass
+
+
+class IrisSystemPermissionError(IrisSystemError):
+    reason = "Permission denied"
+
+    def __init__(self, path):
+        message = "Password-less access to %s was refused. Check your /etc/sudoers file." % path.as_uri()
+        super().__init__(message)
+
+
+class IrisSystemMissingError(IrisSystemError):
+    reason = "Not found"
+
+    def __init__(self, path):
+        message = "Unable to access %s." % path.as_uri()
+        super().__init__(message)
+
+
 class IrisSystemThread(Thread):
     def __init__(self, action, callback):
         Thread.__init__(self)
@@ -19,32 +40,34 @@ class IrisSystemThread(Thread):
 
         try:
             self.can_run()
-        except Exception as e:
+        except IrisSystemError as e:
             logger.error(e)
 
             error = {
-                'message': "Permission denied",
-                'description': str(e)
+                'message': e.reason,
+                'description': e.message
             }
             
             return {
                 'error': error
             }
 
-        logger.debug("sudo %s %s", self.script_path, self.action)
+        logger.debug("sudo %s %s", self.script_path.as_uri(), self.action)
 
-        proc = subprocess.Popen(["sudo", str(self.script_path), self.action],
+        proc = subprocess.Popen([b"sudo", bytes(self.script_path), self.action.encode()],
             stdout=subprocess.PIPE, 
-            stderr=subprocess.STDOUT)
+            stderr=subprocess.PIPE)
         
         stdout,stderr = proc.communicate()
 
         if stderr:
-            logger.error(stderr.decode())
-            self.callback(None, { 'error': stderr.decode() })
+            error_string = os.fsdecode(stderr)
+            logger.error(error_string)
+            self.callback(None, {'error': error_string})
         else:
-            logger.info(stdout.decode())
-            self.callback({ 'output': stdout.decode() }, None)
+            response_string = os.fsdecode(stdout)
+            logger.info(response_string)
+            self.callback({'output': response_string}, None)
 
 
 
@@ -54,14 +77,16 @@ class IrisSystemThread(Thread):
     # @return boolean or exception
     ##
     def can_run(self, *args, **kwargs):
+        if not self.script_path.is_file():
+            raise IrisSystemMissingError(self.script_path)
 
         # Attempt an empty call to our system file
-        process = subprocess.Popen("sudo -n %s check" % self.script_path, stdout=subprocess.PIPE, stderr=subprocess.PIPE, shell=True)
+        process = subprocess.Popen(b"sudo -n %s check" % bytes(self.script_path), stdout=subprocess.PIPE, stderr=subprocess.PIPE, shell=True)
         result, error = process.communicate()
         exitCode = process.wait()
 
         # Some kind of failure, so we can't run any commands this way
         if exitCode > 0:
-            raise Exception("Password-less access to %s was refused. Check your /etc/sudoers file." % self.script_path)
+            raise IrisSystemPermissionError(self.script_path)
         else:
             return True