diff --git a/ajax/admin.php b/ajax/admin.php
index 48b6ea05..524b9780 100644
--- a/ajax/admin.php
+++ b/ajax/admin.php
@@ -43,7 +43,8 @@ wAAAQACAAAAAAAAAAAAAAAAAAAAAAACAAAAAtXN1ZwuGxCTlwgAKyz5rkQAAAAF1c3VnC4bEJOXCAArL
  
 		$params = ' --headless --convert-to ' . escapeshellarg($targetFilter) . ' --outdir ' 
 			. escapeshellarg($outdir) 
-			. ' --writer '. escapeshellarg($infile) . ' 2>&1';
+			. ' --writer '. escapeshellarg($infile) 
+			. ' -env:UserInstallation=file://' . escapeshellarg(get_temp_dir()) . ' 2>&1'
 		;
 		file_put_contents($infile, $input);
  
diff --git a/lib/converter.php b/lib/converter.php
index 5a5a9144..50fa1f00 100644
--- a/lib/converter.php
+++ b/lib/converter.php
@@ -49,7 +49,7 @@ class Converter {
 		$params = ' --headless --convert-to ' . $targetFilter . ' --outdir ' 
 				. escapeshellarg($outdir) 
 				. ' --writer '. escapeshellarg($infile)
-				. ' -env:UserInstallation=file://' . get_temp_dir()
+				. ' -env:UserInstallation=file://' . escapeshellarg(get_temp_dir())
 		;
 		
 		file_put_contents($infile, $input);