Ableton Forum

Hi, i am working on a beat in Ableton using only midi clips. My problem is that the tempo is inconsistent every time i open the set. For example, the set will play at the intended tempo of 120 bpm one day, and i will open the same set the next day and it will play at either a faster or slower tempo. What i don't understand is that the tempo doesn't physically change but the song just sounds way slower or faster at times.

I am using top of the line MacBook pro 16gb Ram and Apollo Twin quad Interface. Additionally, my sample rate of 44.1 matches my interface sample rate. So i don't know what is causing the random tempo changes. Please i need help!!!!