diff --git a/src/apps.js b/src/apps.js
index a595357e7..8792de3cd 100644
--- a/src/apps.js
+++ b/src/apps.js
@@ -1551,7 +1551,7 @@ function clone(appId, data, user, auditSource, callback) {
             error = validatePortBindings(portBindings, manifest);
             if (error) return callback(error);
 
-            const mailboxName = mailboxNameForLocation(location, manifest);
+            const mailboxName = app.mailboxName.endsWith('.app') ? mailboxNameForLocation(location, manifest) : app.mailboxName;
             const locations = [{subdomain: location, domain}];
             validateLocations(locations, function (error, domainObjectMap) {
                 if (error) return callback(error);