How can I generate peak files to load my video clips?

Dear Community Forum

I have created a 60-min film in Premiere Pro 2015. I want to export an AAF file to send to my sound designer. Because my laptop isn't powerful enough to export an AAF, I have opened my project on another laptop, using Premiere Pro 2018.

My timeline is open on the other laptop, but more than half of my video clips have gone grey; they should be colour. On a previous occasion, when I opened my project file, Premiere generated peak files, thereby converting all my video clips into full colour. This time, however, Premiere hasn't generated peak files. What should I do to resolve this?

Thank you for your time and help.

Dorothy