Thanks for this several suggestions and reply.
No, I am not it person

But I tried many thing and change nothing ...
I am sure that I must uninstall multibit and reinstall but I am scare to lost my money with this process ...
If I do :
- export key. My key will be save in my computer, right ?
- After I uninstall multibit
- After I reinstall multibit
- and for finish, I import my key in multibit.
Like this, I don't lost something about my btc's, right ?
What I can get with this process ??
Instead of importing your private keys, just backup your wallet.
try this:
Go to C:\Users\(user name)\AppData\Roaming\MultiBit
copy all data in that folder and uninstall multibit and delete this folder ► C:\Users\(user name)\AppData\Roaming\
MultiBitNow reinstal multibit and paste the content you copied at ► C:\Users\(user name)\AppData\Roaming\MultiBit It'll ask "file already exist replace?" Click Yes.
Now open multibit

it'll synchronous to till date. This will help you.
~Rude Boy