If you delete your conversation history, you can’t recover it. Conversation history includes:
- Instant messages
- Voice messages
- Video messages
- Text messages (SMS)
- Details of files you’ve sent and received
When you delete your conversation history, it’s only deleted from the computer that you’re using – it’s still visible on other devices where you've used the same Skype account, unless you delete it there too.
To delete your entire conversation history:
In the menu bar, select Skype and then select Preferences....
On the Privacy tab, click Delete All Chat History....
In the confirmation box, click Delete All. All of your instant messages, SMS, file transfers, voice and video messages are deleted and cannot be recovered.