25 fps footage keeps getting out of sync. HELP!

[jonathans52264784]

Im editing some 25 fps source footage in a 23.976 sequence (the spot will be broadcast in the US.)

Its only a :30 spot pulling from about 20 x 11 minute episodes encoded 1920 x 1080 prores 422.

Every few minutes my machine loses its sync and i have to restart premiere pro again to get it back in sync for the few minutes it will allow.

Can anyone think of a way to make this work more smoothly?

Thanks!

Jon 

PP CC v.12.1.2

Mac Pro cheese grater tower 

2 x 2.26 ghz quad-core intel xenon

32 GB memory

ati radeon HD 5770 1024 graphics

OS X El Capitan

[Ann Bens]

Convert the 25 fps to an intermediate codec with the desirede framerate and use that in stead of the original.