Container disk1 shows up duplicated on Disk Utility

Hello guillem2000,

Thanks for using Apple Support Communities! So you're having issues with duplicate containers on your Mac; let's look into this more.

This is not normal and it would be best to backup your Mac and then reinstall. The following support article provides some troubleshooting steps to try for this behavior:

Back up your Mac with Time Machine - Apple Support

How to erase a disk for Mac - Apple Support

Restore your Mac from a backup - Apple Support

Hope this helps.

Best Regards.