OK. I restore the release 13 and a backup of my wallet.
Everything is now OK.
I notice that I had the 32 bit release of the release 13 and I had installed the 64 bits release of the 15.0.1.
Do you think that can be my problem ?
Ah yes that'll probably have been the issue. Anyway hopefully you can try putting a 32 bit version of 0.15.0.1 instead to see if that solves the issue and it works. I'm not sure bitcoin core 13 is compatible with segwit2x but it should be compatible with segwit.