diff --git a/inc/inc.ClassConversionServiceExec.php b/inc/inc.ClassConversionServiceExec.php
index bf973b6c6..2bf66982d 100644
--- a/inc/inc.ClassConversionServiceExec.php
+++ b/inc/inc.ClassConversionServiceExec.php
@@ -83,6 +83,7 @@ class SeedDMS_ConversionServiceExec extends SeedDMS_ConversionServiceBase {
 		fclose($pipes[0]);
 		fclose($pipes[1]);
 		fclose($pipes[2]);
+
 		if ($timeleft <= 0) {
 			proc_terminate($process);
 			throw new Exception("command timeout after ".$orgtimeout." secs on: " . $cmd);
@@ -98,6 +99,10 @@ class SeedDMS_ConversionServiceExec extends SeedDMS_ConversionServiceBase {
 		$this->to = $to;
 		$this->cmd = $cmd;
 		$this->timeout = ((int) $timeout) ? (int) $timeout : 5;
+		/* Command fails if stderr is not empty */
+		$this->failonstderr = true;
+		/* Command fails if return code is not 0 */
+		$this->failonretcode = false;
 	}
 
 	public function getInfo() {
@@ -178,9 +183,17 @@ class SeedDMS_ConversionServiceExec extends SeedDMS_ConversionServiceBase {
 		}
 		if(!empty($ret['stderr'])) {
 			if($this->logger) {
-				$this->logger->log('Conversion from '.$this->from.' to '.$this->to.' with cmd "'.$this->cmd.'" failed: '.$ret['stderr'], PEAR_LOG_ERR);
+				$this->logger->log('Conversion from '.$this->from.' to '.$this->to.' with cmd "'.$this->cmd.'" failed: stderr is '.$ret['stderr'], PEAR_LOG_ERR);
 			}
-			return false;
+			if ($this->failonstderr)
+				return false;
+		}
+		if(!empty($ret['return'])) {
+			if($this->logger) {
+				$this->logger->log('Conversion from '.$this->from.' to '.$this->to.' with cmd "'.$this->cmd.'" failed: Error code '.$ret['return'], PEAR_LOG_ERR);
+			}
+			if ($this->failonretcode)
+				return false;
 		}
 		$end = microtime(true);
 		if($this->logger) {