You can use the three solutions to solving Windows 10 grub rescue error. In order to prevent this issue from happening again, you should pay attention to the following points: If you want to delete the Ubuntu operating system on both systems, you should do it the right way. If you want to reinstall the Ubuntu operating system, make sure you install the new system to the original partition. You'd better not restore your Ubuntu to the old version, or you will damage Grub.