diff --git a/Duplicati/Server/webroot/ngax/scripts/directives/parseAdvancedOption.js b/Duplicati/Server/webroot/ngax/scripts/directives/parseAdvancedOption.js
index fde2b57af..7e41f3835 100644
--- a/Duplicati/Server/webroot/ngax/scripts/directives/parseAdvancedOption.js
+++ b/Duplicati/Server/webroot/ngax/scripts/directives/parseAdvancedOption.js
@@ -179,7 +179,7 @@ backupApp.directive('parseAdvancedOptionSizeNumber', function(AppUtils) {
                 if (name == null)
                     return null;
 
-                return name + '=' + txt + multiplier;
+                return name + '=' + (txt || '0') + (multiplier || '');
             });
 
             ctrl[0].$formatters.push(function(src) {
@@ -231,7 +231,7 @@ backupApp.directive('parseAdvancedOptionSizeMultiplier', function(AppUtils) {
                 if (name == null)
                     return null;
 
-                return name + '=' + (number || '') + txt;
+                return name + '=' + (number || '0') + (txt || '');
             });
 
             ctrl[0].$formatters.push(function(src) {
diff --git a/Duplicati/Server/webroot/ngax/scripts/directives/parseSizeNumber.js b/Duplicati/Server/webroot/ngax/scripts/directives/parseSizeNumber.js
index 05f6b7466..708a210f7 100644
--- a/Duplicati/Server/webroot/ngax/scripts/directives/parseSizeNumber.js
+++ b/Duplicati/Server/webroot/ngax/scripts/directives/parseSizeNumber.js
@@ -9,8 +9,7 @@ backupApp.directive('parseSizeNumber', function(AppUtils) {
             var multiplier = null;
 
             ctrl[0].$parsers.push(function(txt) {
-                txt = txt || '0';
-                return txt + (multiplier || '');
+                return (txt || '0') + (multiplier || '');
             });
 
             ctrl[0].$formatters.push(function(src) {