When I updated leap to version: 2020.1.0.24 (64-Bit), it doesn't run and it shows me this message. The same areas used to run perfectly before I updated I was using versions 2020.1.0.19. How can I fix this please?

Yes, LEAP 2020.1.24 does some additional error checking now and it has identified what it thinks is a possible problem in your model. You set up your model to use historical dispatch in 2009, but it looks like you have not entered any historical dispatch data for any of the processes within the Historical Production variable. Maybe you really did mean to do that, but LEAP is trying to be helpful and point this out to you because it is a common error made by many users. If it is an error, then you can fix it by putting in data in the historical production variable for 2009. If you really did mean to do this, then check the "Don't Show This Again" box and then click "no".

Hope this helps!

Charlie