Crash at start, get Back work

Hi !
I worked all day on a blueprint, and then my engine just crashed.
When I tried to restart it, it crashed again !
So I checked the logs, and here is my error :

Fatal error: [File:D:\Build\++UE4+Release-4.14+Compile\Sync\Engine\Source\Runtime\CoreUObject\Private\Templates\Casts.cpp] [Line: 11] 
Cast of LinkerPlaceholderExportObject /Game/PROJECT/JeuVannes/Sections/MainValveGame.MainValveGame_C:SH1_GEN_VARIABLE.SH1_GEN_VARIABLE_BP_Section_C_CAT to Actor failed

So I moved the blueprint outside of the project. And I restart it. It’s work, but how to get my blueprint work again ? I can’t spend one more day to redone it ! (When I put it back in the project, it crash the engine.)

If anybody have a solution,
Thanks !