diff --git a/docs/content/s3.md b/docs/content/s3.md
index 265d9190b..67f940117 100644
--- a/docs/content/s3.md
+++ b/docs/content/s3.md
@@ -552,6 +552,15 @@ the object(s) in question before using rclone.
 Note that rclone only speaks the S3 API it does not speak the Glacier
 Vault API, so rclone cannot directly access Glacier Vaults.
 
+### Object-lock enabled S3 bucket
+
+According to AWS's [documentation on S3 Object Lock](https://docs.aws.amazon.com/AmazonS3/latest/userguide/object-lock-overview.html#object-lock-permission):
+
+> If you configure a default retention period on a bucket, requests to upload objects in such a bucket must include the Content-MD5 header.
+
+As mentioned in the [Hashes](#hashes) section, small files that are not uploaded as multipart, use a different tag, causing the upload to fail.
+A simple solution is to set the `--s3-upload-cutoff 0` and force all the files to be uploaded as multipart.
+
 {{< rem autogenerated options start" - DO NOT EDIT - instead edit fs.RegInfo in backend/s3/s3.go then run make backenddocs" >}}
 ### Standard options