diff --git a/src/Infrastructure.EntityFramework/Repositories/CipherRepository.cs b/src/Infrastructure.EntityFramework/Repositories/CipherRepository.cs
index 6f81e5952..c3268aa3f 100644
--- a/src/Infrastructure.EntityFramework/Repositories/CipherRepository.cs
+++ b/src/Infrastructure.EntityFramework/Repositories/CipherRepository.cs
@@ -562,7 +562,8 @@ public class CipherRepository : Repository<Core.Entities.Cipher, Cipher, Guid>,
             var attachments = string.IsNullOrWhiteSpace(cipher.Attachments) ?
                 new Dictionary<string, CipherAttachment.MetaData>() :
                 JsonConvert.DeserializeObject<Dictionary<string, CipherAttachment.MetaData>>(cipher.Attachments);
-            attachments.Add(attachment.AttachmentId, JsonConvert.DeserializeObject<CipherAttachment.MetaData>(attachment.AttachmentData));
+            var metaData = JsonConvert.DeserializeObject<CipherAttachment.MetaData>(attachment.AttachmentData);
+            attachments[attachment.AttachmentId] = metaData;
             cipher.Attachments = JsonConvert.SerializeObject(attachments);
             await dbContext.SaveChangesAsync();