The XML you provided was not well-formed or did not validate against our published schema

[xin-young]

i work follow the document，but a exception appear when merge files.
http://docs.aws.amazon.com/zh_cn/AmazonS3/latest/dev/LLuploadFileDotNet.html

[normj]

When you call CompleteMultipartUploadAsync you need to fill in the PartETags collection on the CompleteMultipartUploadRequest object with all of the parts you uploaded. We definitely need a better error message.

You can also use Amazon.S3.Transfer.TransferUtility which will automatically take care of the multipart upload.

[xin-young]

Good suggestions.The first instance of the document misled me.I want to upload data directly from the Web page to S3,so choose this way.

[fractos]

Just hit this - you definitely need better error messages.