An internal error number 1060 happend. 500 Internal Server Error

[cdamken]

Expected behaviour

All users can use the sync-client without problem

Actual behaviour

All users exept one can use the sync-client

Steps to reproduce

There are about 4000 users, and only one receive the message: "An internal error number 1060 happend. 500 Internal Server Error" in the sync-client.
The user have try in different computers with the same problem.
The user can use the WebUI without problems.

Server configuration

ownCloud version:
6.0.3

Client configuration

1.5.4 and 1.6.1

Logs

S3-ownCloud\Shared\owncloud\support\customer-tickets-history\1060 error 500 Server

I was thinking it was client problem: owncloud/client#1951

But @dragotin pointed: "500 server error"