i don't have any other positional representation. I got it by removing a constraint. I added a constraint that it was in a sub assembly. I made this sub assembly flexible in my actual assembly. Since there everything works. I added an other constraints to block the flexible movement and i believe from there everything got stuck. The issue is that a kept adding stuff and constraint but there was no error. I realized something got wrong when few click later I tried to move flexible constraints. It hard to know and find when i made the mistake without error flag. Because it was 15 minute earlier I found it pretty easily. But imagine if I would have saved the project and work on it few days later. Without any error flag I would have lost time to found it.