I have a Seagate 2TB USB2 hard drive, ext4 formatted. If I plug it in to my system and boot, PC gets stuck at welcome to grub. If I restart without the USB drive plugged in, the system boots normally. I can then plug the drive and use it.I am using Debian GNU/Linux jessie/sid updated to latest.Ubuntu livecds/usbs boot fine.lsusb (of the external drive):Bus 001 Device 006: ID 0bc2:3332 Seagate RSS LLC Expansiongrub-pc version: 2.00-14Motherboard only has USB2 ports (Intel H55TC)BIOS is up to date (both old and new firmware experienced the same problem).What could be causing this?(testable speculations are welcome, because I ran out of ideas).Note: Before I found the USB drive was the cause I would simply boot around 10 times, and eventually it will boot normally.Here is my grub.cfg## DO NOT EDIT THIS FILE## It is automatically generated by grub-mkconfig using templates# from /etc/grub.d and settings from /etc/default/grub#### BEGIN /etc/grub.d/00_header ###if [ -s $prefix/grubenv ]; thenload_envfiset default=0if [ x${feature_menuentry_id} = xy ]; thenmenuentry_id_option=--idelsemenuentry_id_option=fiexport menuentry_id_optionif [ ${prev_saved_entry} ]; thenset saved_entry=${prev_saved_entry}save_env saved_entryset prev_saved_entry=save_env prev_saved_entryset boot_once=truefifunction savedefault {if [ -z ${boot_once} ]; then    saved_entry=${chosen}    save_env saved_entryfi}function load_video {if [ x$feature_all_video_module = xy ]; then    insmod all_videoelse    insmod efi_gop    insmod efi_uga    insmod ieee1275_fb    insmod vbe    insmod vga    insmod video_bochs    insmod video_cirrusfi}terminal_input consoleterminal_output consoleset timeout=5### END /etc/grub.d/00_header ###### BEGIN /etc/grub.d/05_debian_theme ###set menu_color_normal=cyan/blueset menu_color_highlight=white/blue### END /etc/grub.d/05_debian_theme ###### BEGIN /etc/grub.d/10_linux ###menuentry 'Debian GNU/Linux' --class debian --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-simple-2f0165f3-2087-4157-b1e6-f707a995827b' {        load_video        insmod gzio        insmod part_msdos        insmod part_msdos        insmod diskfilter        insmod mdraid09        insmod ext2        set root='mduuid/019e28032b26f1e0e368bf24bd0fce41'        if [ x$feature_platform_search_hint = xy ]; then        search --no-floppy --fs-uuid --set=root --hint='mduuid/019e28032b26f1e0e368bf24bd0fce41'  2f0165f3-2087-4157-b1e6-f707a995827b        else        search --no-floppy --fs-uuid --set=root 2f0165f3-2087-4157-b1e6-f707a995827b        fi        echo    'Loading Linux 3.9-1-686-pae ...'        linux   /boot/vmlinuz-3.9-1-686-pae root=UUID=2f0165f3-2087-4157-b1e6-f707a995827b ro  hdd=noprobe        echo    'Loading initial ramdisk ...'        initrd  /boot/initrd.img-3.9-1-686-pae}submenu 'Advanced options for Debian GNU/Linux' $menuentry_id_option 'gnulinux-advanced-2f0165f3-2087-4157-b1e6-f707a995827b' {        menuentry 'Debian GNU/Linux, with Linux 3.9-1-686-pae' --class debian --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-3.9-1-686-pae-advanced-2f0165f3-2087-4157-b1e6-f707a995827b' {                load_video                insmod gzio                insmod part_msdos                insmod part_msdos                insmod diskfilter                insmod mdraid09                insmod ext2                set root='mduuid/019e28032b26f1e0e368bf24bd0fce41'                if [ x$feature_platform_search_hint = xy ]; then                search --no-floppy --fs-uuid --set=root --hint='mduuid/019e28032b26f1e0e368bf24bd0fce41'  2f0165f3-2087-4157-b1e6-f707a995827b                else                search --no-floppy --fs-uuid --set=root 2f0165f3-2087-4157-b1e6-f707a995827b                fi                echo    'Loading Linux 3.9-1-686-pae ...'                linux   /boot/vmlinuz-3.9-1-686-pae root=UUID=2f0165f3-2087-4157-b1e6-f707a995827b ro  hdd=noprobe                echo    'Loading initial ramdisk ...'                initrd  /boot/initrd.img-3.9-1-686-pae        }        menuentry 'Debian GNU/Linux, with Linux 3.9-1-686-pae (recovery mode)' --class debian --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-3.9-1-686-pae-recovery-2f0165f3-2087-4157-b1e6-f707a995827b' {                load_video                insmod gzio                insmod part_msdos                insmod part_msdos                insmod diskfilter                insmod mdraid09                insmod ext2                set root='mduuid/019e28032b26f1e0e368bf24bd0fce41'                if [ x$feature_platform_search_hint = xy ]; then                search --no-floppy --fs-uuid --set=root --hint='mduuid/019e28032b26f1e0e368bf24bd0fce41'  2f0165f3-2087-4157-b1e6-f707a995827b                else                search --no-floppy --fs-uuid --set=root 2f0165f3-2087-4157-b1e6-f707a995827b                fi                echo    'Loading Linux 3.9-1-686-pae ...'                linux   /boot/vmlinuz-3.9-1-686-pae root=UUID=2f0165f3-2087-4157-b1e6-f707a995827b ro single                 echo    'Loading initial ramdisk ...'                initrd  /boot/initrd.img-3.9-1-686-pae        }        menuentry 'Debian GNU/Linux, with Linux 3.2.0-4-686-pae' --class debian --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-3.2.0-4-686-pae-advanced-2f0165f3-2087-4157-b1e6-f707a995827b' {                load_video                insmod gzio                insmod part_msdos                insmod part_msdos                insmod diskfilter                insmod mdraid09                insmod ext2                set root='mduuid/019e28032b26f1e0e368bf24bd0fce41'                if [ x$feature_platform_search_hint = xy ]; then                search --no-floppy --fs-uuid --set=root --hint='mduuid/019e28032b26f1e0e368bf24bd0fce41'  2f0165f3-2087-4157-b1e6-f707a995827b                else                search --no-floppy --fs-uuid --set=root 2f0165f3-2087-4157-b1e6-f707a995827b                fi                echo    'Loading Linux 3.2.0-4-686-pae ...'                linux   /boot/vmlinuz-3.2.0-4-686-pae root=UUID=2f0165f3-2087-4157-b1e6-f707a995827b ro  hdd=noprobe                echo    'Loading initial ramdisk ...'                initrd  /boot/initrd.img-3.2.0-4-686-pae        }        menuentry 'Debian GNU/Linux, with Linux 3.2.0-4-686-pae (recovery mode)' --class debian --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-3.2.0-4-686-pae-recovery-2f0165f3-2087-4157-b1e6-f707a995827b' {                load_video                insmod gzio                insmod part_msdos                insmod part_msdos                insmod diskfilter                insmod mdraid09                insmod ext2                set root='mduuid/019e28032b26f1e0e368bf24bd0fce41'                if [ x$feature_platform_search_hint = xy ]; then                search --no-floppy --fs-uuid --set=root --hint='mduuid/019e28032b26f1e0e368bf24bd0fce41'  2f0165f3-2087-4157-b1e6-f707a995827b                else                search --no-floppy --fs-uuid --set=root 2f0165f3-2087-4157-b1e6-f707a995827b                fi                echo    'Loading Linux 3.2.0-4-686-pae ...'                linux   /boot/vmlinuz-3.2.0-4-686-pae root=UUID=2f0165f3-2087-4157-b1e6-f707a995827b ro single                 echo    'Loading initial ramdisk ...'                initrd  /boot/initrd.img-3.2.0-4-686-pae        }        menuentry 'Debian GNU/Linux, with Linux 3.2.0-3-686-pae' --class debian --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-3.2.0-3-686-pae-advanced-2f0165f3-2087-4157-b1e6-f707a995827b' {                load_video                insmod gzio                insmod part_msdos                insmod part_msdos                insmod diskfilter                insmod mdraid09                insmod ext2                set root='mduuid/019e28032b26f1e0e368bf24bd0fce41'                if [ x$feature_platform_search_hint = xy ]; then                search --no-floppy --fs-uuid --set=root --hint='mduuid/019e28032b26f1e0e368bf24bd0fce41'  2f0165f3-2087-4157-b1e6-f707a995827b                else                search --no-floppy --fs-uuid --set=root 2f0165f3-2087-4157-b1e6-f707a995827b                fi                echo    'Loading Linux 3.2.0-3-686-pae ...'                linux   /boot/vmlinuz-3.2.0-3-686-pae root=UUID=2f0165f3-2087-4157-b1e6-f707a995827b ro  hdd=noprobe                echo    'Loading initial ramdisk ...'                initrd  /boot/initrd.img-3.2.0-3-686-pae        }        menuentry 'Debian GNU/Linux, with Linux 3.2.0-3-686-pae (recovery mode)' --class debian --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-3.2.0-3-686-pae-recovery-2f0165f3-2087-4157-b1e6-f707a995827b' {                load_video                insmod gzio                insmod part_msdos                insmod part_msdos                insmod diskfilter                insmod mdraid09                insmod ext2                set root='mduuid/019e28032b26f1e0e368bf24bd0fce41'                if [ x$feature_platform_search_hint = xy ]; then                search --no-floppy --fs-uuid --set=root --hint='mduuid/019e28032b26f1e0e368bf24bd0fce41'  2f0165f3-2087-4157-b1e6-f707a995827b                else                search --no-floppy --fs-uuid --set=root 2f0165f3-2087-4157-b1e6-f707a995827b                fi                echo    'Loading Linux 3.2.0-3-686-pae ...'                linux   /boot/vmlinuz-3.2.0-3-686-pae root=UUID=2f0165f3-2087-4157-b1e6-f707a995827b ro single                 echo    'Loading initial ramdisk ...'                initrd  /boot/initrd.img-3.2.0-3-686-pae        }        menuentry 'Debian GNU/Linux, with Linux 3.2.0-2-686-pae' --class debian --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-3.2.0-2-686-pae-advanced-2f0165f3-2087-4157-b1e6-f707a995827b' {                load_video                insmod gzio                insmod part_msdos                insmod part_msdos                insmod diskfilter                insmod mdraid09                insmod ext2                set root='mduuid/019e28032b26f1e0e368bf24bd0fce41'                if [ x$feature_platform_search_hint = xy ]; then                search --no-floppy --fs-uuid --set=root --hint='mduuid/019e28032b26f1e0e368bf24bd0fce41'  2f0165f3-2087-4157-b1e6-f707a995827b                else                search --no-floppy --fs-uuid --set=root 2f0165f3-2087-4157-b1e6-f707a995827b                fi                echo    'Loading Linux 3.2.0-2-686-pae ...'                linux   /boot/vmlinuz-3.2.0-2-686-pae root=UUID=2f0165f3-2087-4157-b1e6-f707a995827b ro  hdd=noprobe                echo    'Loading initial ramdisk ...'                initrd  /boot/initrd.img-3.2.0-2-686-pae        }        menuentry 'Debian GNU/Linux, with Linux 3.2.0-2-686-pae (recovery mode)' --class debian --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-3.2.0-2-686-pae-recovery-2f0165f3-2087-4157-b1e6-f707a995827b' {                load_video                insmod gzio                insmod part_msdos                insmod part_msdos                insmod diskfilter                insmod mdraid09                insmod ext2                set root='mduuid/019e28032b26f1e0e368bf24bd0fce41'                if [ x$feature_platform_search_hint = xy ]; then                search --no-floppy --fs-uuid --set=root --hint='mduuid/019e28032b26f1e0e368bf24bd0fce41'  2f0165f3-2087-4157-b1e6-f707a995827b                else                search --no-floppy --fs-uuid --set=root 2f0165f3-2087-4157-b1e6-f707a995827b                fi                echo    'Loading Linux 3.2.0-2-686-pae ...'                linux   /boot/vmlinuz-3.2.0-2-686-pae root=UUID=2f0165f3-2087-4157-b1e6-f707a995827b ro single                 echo    'Loading initial ramdisk ...'                initrd  /boot/initrd.img-3.2.0-2-686-pae        }}### END /etc/grub.d/10_linux ###### BEGIN /etc/grub.d/20_ipxe ###menuentry Network boot (iPXE) --users  --class network {        insmod part_msdos        insmod part_msdos        insmod diskfilter        insmod mdraid09        insmod ext2        set root='mduuid/019e28032b26f1e0e368bf24bd0fce41'        if [ x$feature_platform_search_hint = xy ]; then        search --no-floppy --fs-uuid --set=root --hint='mduuid/019e28032b26f1e0e368bf24bd0fce41'  2f0165f3-2087-4157-b1e6-f707a995827b        else        search --no-floppy --fs-uuid --set=root 2f0165f3-2087-4157-b1e6-f707a995827b        fi        linux16 /boot/ipxe.lkrn}### END /etc/grub.d/20_ipxe ###### BEGIN /etc/grub.d/20_linux_xen ###### END /etc/grub.d/20_linux_xen ###### BEGIN /etc/grub.d/20_memtest86 ###### END /etc/grub.d/20_memtest86 ###### BEGIN /etc/grub.d/20_memtest86+ ###menuentry Memory test (memtest86+) {        insmod part_msdos        insmod part_msdos        insmod diskfilter        insmod mdraid09        insmod ext2        set root='mduuid/019e28032b26f1e0e368bf24bd0fce41'        if [ x$feature_platform_search_hint = xy ]; then        search --no-floppy --fs-uuid --set=root --hint='mduuid/019e28032b26f1e0e368bf24bd0fce41'  2f0165f3-2087-4157-b1e6-f707a995827b        else        search --no-floppy --fs-uuid --set=root 2f0165f3-2087-4157-b1e6-f707a995827b        fi        linux16 /boot/memtest86+.bin}menuentry Memory test (memtest86+, serial console 115200) {        insmod part_msdos        insmod part_msdos        insmod diskfilter        insmod mdraid09        insmod ext2        set root='mduuid/019e28032b26f1e0e368bf24bd0fce41'        if [ x$feature_platform_search_hint = xy ]; then        search --no-floppy --fs-uuid --set=root --hint='mduuid/019e28032b26f1e0e368bf24bd0fce41'  2f0165f3-2087-4157-b1e6-f707a995827b        else        search --no-floppy --fs-uuid --set=root 2f0165f3-2087-4157-b1e6-f707a995827b        fi        linux16 /boot/memtest86+.bin console=ttyS0,115200n8}menuentry Memory test (memtest86+, experimental multiboot) {        insmod part_msdos        insmod part_msdos        insmod diskfilter        insmod mdraid09        insmod ext2        set root='mduuid/019e28032b26f1e0e368bf24bd0fce41'        if [ x$feature_platform_search_hint = xy ]; then        search --no-floppy --fs-uuid --set=root --hint='mduuid/019e28032b26f1e0e368bf24bd0fce41'  2f0165f3-2087-4157-b1e6-f707a995827b        else        search --no-floppy --fs-uuid --set=root 2f0165f3-2087-4157-b1e6-f707a995827b        fi        multiboot       /boot/memtest86+_multiboot.bin}menuentry Memory test (memtest86+, serial console 115200, experimental multiboot) {        insmod part_msdos        insmod part_msdos        insmod diskfilter        insmod mdraid09        insmod ext2        set root='mduuid/019e28032b26f1e0e368bf24bd0fce41'        if [ x$feature_platform_search_hint = xy ]; then        search --no-floppy --fs-uuid --set=root --hint='mduuid/019e28032b26f1e0e368bf24bd0fce41'  2f0165f3-2087-4157-b1e6-f707a995827b        else        search --no-floppy --fs-uuid --set=root 2f0165f3-2087-4157-b1e6-f707a995827b        fi        multiboot       /boot/memtest86+_multiboot.bin console=ttyS0,115200n8}### END /etc/grub.d/20_memtest86+ ###### BEGIN /etc/grub.d/30_os-prober ###### END /etc/grub.d/30_os-prober ###### BEGIN /etc/grub.d/30_uefi-firmware ###### END /etc/grub.d/30_uefi-firmware ###### BEGIN /etc/grub.d/40_custom #### This file provides an easy way to add custom menu entries.  Simply type the# menu entries you want to add after this comment.  Be careful not to change# the 'exec tail' line above.### END /etc/grub.d/40_custom ###### BEGIN /etc/grub.d/41_custom ###if [ -f  ${config_directory}/custom.cfg ]; thensource ${config_directory}/custom.cfgelif [ -z ${config_directory} -a -f  $prefix/custom.cfg ]; thensource $prefix/custom.cfg;fi### END /etc/grub.d/41_custom ###
USB3 drive plugged in to PC makes computer hang on welcome to grub
debian;boot;grub;usb drive