Consider the following scenario:
You type several messages into a conversation window in Microsoft Lync 2013.
Note Only the time stamp of the first message that you typed will appear in the conversation.
You try to copy and then paste these messages into other applications, such as Microsoft Word or Notepad.
In this scenario, time stamp of each message appears in the pasted content.
This issue occurs because Lync 2013 sets the time stamps of continuous message that a user typed to invisible. Therefore, when you copy continuous messages from a Lync 2013 conversation, the invisible time stamps are selected.
To resolve this issue, install the following update:
2889929 October 2014 update for Lync 2013 (KB2889929)