No sound on play back

[Pablo007]

When I open a recent session that i have been working on in pro tools 10 I get a message that says the I O settings have changed. When the session screen comes up I hit the space bar but no sound. I have done nothing to change the settings. I go to the io settings page and the default button is grey'd out also the audition button shows nothing. This first happened last Friday. I don't understand why this has happened as now I can not hear any of my work ?

[Meads]

Sounds like PT didn't recognize your audio interface, and selected your soundcard or aggregate i/o instead.
Check the connection of your interface to your workstation, then go to Playback Engine and make sure, your interface is selected.

[Pablo007]

Hi thanks but

There is no interface connected just the keyboard and mouse and of course the ilok

On Thursday last week this happened I spent over an hour attempting to find what I could do but nothing worked.

I really don't know what to do next.