diff --git a/src/app/services/cryptoService.js b/src/app/services/cryptoService.js
index 44c1aa3250..8c0dfc8a8a 100644
--- a/src/app/services/cryptoService.js
+++ b/src/app/services/cryptoService.js
@@ -354,7 +354,7 @@ angular
             var ivBytes = forge.util.decode64(encPieces[0]);
             var ctBytes = forge.util.decode64(encPieces[1]);
 
-            if (key.macKey) {
+            if (key.macKey && encPieces.length > 2) {
                 var computedMac = computeMac(ctBytes, ivBytes, key.macKey);
                 if (computedMac !== encPieces[2]) {
                     console.error('MAC failed.');