Troubleshooting installation of debian os
After trying debian on an old workstation, I find there are some pitfalls and tricks: It is recommended to install the minimal base system (with no GUI) using the USB installer first. Since installation of GUI is through network and improper configured mirror will dramatically slow down the installation process. Each operating systems need to be installed into a primary partition and set the bootable flag. Do not erase (format) existing partition containing data. It may not find the grub on your newly installed system. In such case, you need to enter rescue mode by booting from USB and chroot