@mundodisco It is recommended that you use Legacy mode, but, you can get a more detailed explanation on how to work in UEFI mode, in this topic:
https://forum.recalbox.com/topic/17464/dualboot-recalbox-windows-sur-pcs-laptops-avec-bios-ou-uefi-27-04-19?_=1585857631180
I had already recommended reading this topic to you: https://forum.recalbox.com/topic/20672/grub-and-boot-questions?_=1590094003287

I know the focus of the post is to do a dual boot, but there is a lot of useful information in it, and, as I said, the recommendation is to use legacy mode, not UEFI.

@darkmage Is your hardware an Rpi3 or an Rpi3 +?
Have you tried another SD card?
As said @voljega is important to turn off the correct way, shutting down wrongly corrupts the system. Doing a disk check on windows often solves the corrupted system problem.

@baudouin-de-la-ville-bauge le W sous tes yeux en haut de cette page

Thank you!
I fixed it by doing this in recalbox.conf:
global.videomode=default