“Failed to lock variable” SSIS error

Question

I am getting an error randomly for a scheduled SSIS package which runs hourly. The funniest thing is that if I delete the checkpoint file and run the package again it works

Answer 1

Had the same error while debugging. Minimizing the visual studio, I saw pop-up with error message behind it. Clicking OK button rendered correct error in my visual studio. It was about missing column mapping. Worked after fixing it.