diff --git a/Akari.Prototype.Server/Services/ApplicationsManager.cs b/Akari.Prototype.Server/Services/ApplicationsManager.cs
index d572d75..6b853ab 100644
--- a/Akari.Prototype.Server/Services/ApplicationsManager.cs
+++ b/Akari.Prototype.Server/Services/ApplicationsManager.cs
@@ -132,6 +132,13 @@ namespace Akari.Prototype.Server.Services
 
         public bool AddFingerprint(string applicationName, string fingerprintName)
         {
+            if (IsFingerprintRegistered(applicationName, fingerprintName))
+            {
+                _logger.LogDebug($"'{fingerprintName}' is already registered for '{applicationName}'");
+
+                return false;
+            }
+
             // Verify master password
             if (!_masterKeyService.IsLoggedIn)
             {