Why do my sessions randomly play in half time?

I have been experiencing this strange thing where often when I open a session it will play at half speed. I will exit out of PT8 and open the same session again and it will be fine. It is random and I have not discovered the pattern. Any help?

Any chance you could be hitting Shift>Space accidentally? Shift>Space plays half time...

Not that I know of. At first I'm sure I accidently did this. But now I just open random sessions and 3 out of 7 times it is at half speed before I touch anything. This has been happening over a 2 week time period. before that I never had this problem in 6 years of Protools recording.

Just a thought....Half speed and double speed audio can sometimes be a sample rate issue. Next time it happens check the settings of the session and make sure that it's set to what you originally chose. Good luck Dtyd