After installing Elementary (latest version, July 2021) from a USB stick, computer get's UEFI errors when rebooted. The only way to get the installation correct is to disable UEFI and use legacy support, Elementary then works OK. It seems that GRUB is not properly installed/configured, the 1st time installation actually showed a GRUB error. In this same computer I just installed Ubuntu 20 LTS on UEFI and it works w/o issues (Ubuntu and most Linux distros use GRUB, Elementary seems to use GRUB2). My laptop is a Lenovo Idea Pad 5 Flex (end of 2020 model).