Tracks inexplicably not playing

I’ve created a project with quite a few tracks and it was all working fine and I saved it. I come back to it and nothing’s muted or solo but only certain tracks play. It’s midi data using VST instruments. I turn the computer off and on and sometimes it works and and sometimes it does this. Help ?

Check your routing of the tracks and also check the VST Connections. The tracks should go to the Stereo Out and the Stereo Out must be connected to the outputs of your audio interface.
Beyond that, some screenshots and more information may be needed to help.

Thanks. I had been told to delete my images folder for another problem - incorrect waveforms showing in a different project - anyway I hadn’t done this before but I did it now just to see what happened and it has done the trick. Why I do not know but it has , touch wood.

Strange. Glad it worked.