Hi Guys, More 777 woes for me. Both of my CDU's completely freeze pre-flight. I sit on the FO side and I tried the Captain's side too but no luck. It always happens when trying to put in the cost index. I've tried a flight from EGLL - KPHL about five times now with different starting scenarios but it never seems to get past that point. I can tell when it's about to go weird aswell because when I select the VCN8 arrival for KPHL, it doesn't say SEL next to it when I click it, unless I go to another page, then back to that one. The route executes okay and I can do the PERF INIT up until cost index, where I try to put in say 90, and it won't let me put it in. Then on the FO's CDU everything is completely frozen, and on the Captain's side I can navigate pages for a while but not make any inputs at all. Then when I try to load a different panel state from the Captain's CDU it just goes black. I've tried everything I can think of, reinstalling the entire aircraft, trying from different panel states, but it always gets stuck at this phase. The rest of FS is running perfectly and everything else in the plane remains clickable, except perhaps the most important bit of it!