Can't boot Windows after failed Lubuntu installation

Hello Everybody,

This is my first time using Linux. I tried to install Lubuntu alongside Windows 7 in a dual-boot setup, but the installation failed with an error code 1. Now, when I try to boot normally, I get a message saying “Reboot and Select proper Boot device.”

During the Lubuntu installation, I created two partitions on Disk D (Windows is on Disk C). I set up an ext4 filesystem for the root partition and an EFI filesystem for /boot/efi with the boot flag enabled.

I couldn’t find any settings related to UEFI or CSM in the BIOS.

Ubuntu Version: Lubuntu 25.04
Desktop Environment: LXQt
Relevant System informaton: AMD A6-3420M APU with Radeon HD Graphics, Radeon X800 GTO, 4gb ram, two hard drives

Below is the boot-repair report. Should I proceed with the recommended repair?

boot-repair-4ppa2081                                              [20250702_0417]

============================== Boot Info Summary ===============================

 => Windows is installed in the MBR of /dev/sda.
 => Grub2 (v2.00) is installed in the MBR of /dev/sdb and looks at sector 1 of 
    the same hard drive for core.img. core.img is at this location and looks 
    for (hd0,msdos1)/boot/grub. It also embeds following components:
    
    modules
    ---------------------------------------------------------------------------
    biosdisk fshelp fat exfat ext2 ntfs ntfscomp part_msdos
    ---------------------------------------------------------------------------

sda1: __________________________________________________________________________

    File system:       ntfs
    Boot sector type:  Windows 7/2008: NTFS
    Boot sector info:  No errors found in the Boot Parameter Block.
    Operating System:  
    Boot files:        

sda2: __________________________________________________________________________

    File system:       ntfs
    Boot sector type:  Windows 7/2008: NTFS
    Boot sector info:  No errors found in the Boot Parameter Block.
    Operating System:  
    Boot files:        /bootmgr /Boot/BCD

sda3: __________________________________________________________________________

    File system:       ntfs
    Boot sector type:  Windows 7/2008: NTFS
    Boot sector info:  No errors found in the Boot Parameter Block.
    Operating System:  Windows 7
    Boot files:        /bootmgr /Windows/System32/winload.exe

sda4: __________________________________________________________________________

    File system:       Extended Partition
    Boot sector type:  -
    Boot sector info: 

sda5: __________________________________________________________________________

    File system:       ntfs
    Boot sector type:  Windows 7/2008: NTFS
    Boot sector info:  According to the info in the boot sector, sda5 starts 
                       at sector 2048.
    Operating System:  
    Boot files:        

sda6: __________________________________________________________________________

    File system:       ext4
    Boot sector type:  -
    Boot sector info: 
    Operating System:  Ubuntu 25.04
    Boot files:        /etc/fstab /etc/default/grub

sda7: __________________________________________________________________________

    File system:       vfat
    Boot sector type:  FAT32
    Boot sector info:  No errors found in the Boot Parameter Block.
    Operating System:  
    Boot files:        /efi/BOOT/fbx64.efi /efi/BOOT/mmx64.efi 
                       /efi/ubuntu/grubx64.efi /efi/ubuntu/mmx64.efi 
                       /efi/ubuntu/shimx64.efi /efi/ubuntu/grub.cfg

sdb1: __________________________________________________________________________

    File system:       vfat
    Boot sector type:  MSWIN4.1: FAT32
    Boot sector info:  No errors found in the Boot Parameter Block.
    Operating System:  
    Boot files:        /boot/grub/grub.cfg /efi/boot/bootx64.efi 
                       /efi/boot/grubx64.efi /efi/boot/mmx64.efi


================================ 2 OS detected =================================

OS#1 (linux):   Ubuntu 25.04 on sda6
OS#2 (windows):   Windows 7 on sda3

================================ Host/Hardware =================================

CPU architecture: 64-bit
Video: R480 [Radeon X800 GTO] R480 [Radeon X800 GTO] (Secondary) from Advanced Micro Devices, Inc. [AMD/ATI] Advanced Micro Devices, Inc. [AMD/ATI]
Live-session OS is Ubuntu 64-bit (Ubuntu 25.04, plucky, x86_64)

===================================== UEFI =====================================

BIOS/UEFI firmware: 4.6.5(4.6) from American Megatrends Inc.
The firmware is EFI-compatible, and is set in EFI-mode for this live-session.
SecureBoot disabled - This system doesn't support Secure Boot.
BootCurrent: 0003
Timeout: 3 seconds
BootOrder: 0003,0001,0002
Boot0001* Hard Drive 	BBS(HD,,0x0)414d474f414d4e4fa7000000010000006f0054004f00530048004900420041002000440054003000310041004300410031003000300000000501090002000000007fff040002010c00d041030a0000000001010600001103120a000000ffff00007fff040001043e00ef47642dc93ba041ac194d51d01b4ce620002000200020002000200020002000200020003100200054003800530050005500450053004d0000007fff0400414d424f414d4e4f9f000000010000006700200055005300420020004400490053004b00200032002e003000200050004d004100500000000501090002000000007fff040002010c00d041030a000000000101060002120305060002007fff040001043a00ef47642dc93ba041ac194d51d01b4ce6200055005300420020004400490053004b00200032002e003000200050004d004100500000007fff0400414d424f
Boot0002  CD/DVD Drive 	BBS(CDROM,,0x0)414d474f414d4e4fb3000000010000006f0048004c002d00440054002d00530054002000440056004400520041004d00200047004800320034004e0053004400310000000501090003000000007fff040002010c00d041030a0000000001010600001103120a000200ffff00007fff040001043e00ef47642dc93ba041ac194d51d01b4ce631004b0049004500360032003400450031003400200033002000200020002000200020002000200000007fff0400414d424f
Boot0003* UEFI:  USB DISK 2.0 PMAP	PciRoot(0x0)/Pci(0x12,0x2)/USB(2,0)/HD(1,MBR,0x79b378,0x800,0x1ce5800)AMBO

6c4ec35ced47a0bfa4cc96d3570d2e17   sda7/BOOT/fbx64.efi
9f09ebdacbdc7c46269f99c7754bbfd3   sda7/BOOT/mmx64.efi
7ccabe8753cdf1d8f38b81d65b2d9564   sda7/ubuntu/grubx64.efi
9f09ebdacbdc7c46269f99c7754bbfd3   sda7/ubuntu/mmx64.efi
211a377300f24895b42f5ce384344a0c   sda7/ubuntu/shimx64.efi
211a377300f24895b42f5ce384344a0c   sda7/BOOT/BOOTX64.efi

============================= Drive/Partition Info =============================

Disks info: ____________________________________________________________________

sda	: notGPT,	no-BIOSboot,	has---ESP, 	not-usb,	not-mmc, has-os,	has-win,	2048 sectors * 512 bytes

Partitions info (1/3): _________________________________________________________

sda1	: no-os,	64, nopakmgr,	no-docgrub,	nogrub,	nogrubinstall,	no-grubenv,	noupdategrub,	not-far
sda2	: no-os,	64, nopakmgr,	no-docgrub,	nogrub,	nogrubinstall,	no-grubenv,	noupdategrub,	not-far
sda3	: is-os,	64, nopakmgr,	no-docgrub,	nogrub,	nogrubinstall,	no-grubenv,	noupdategrub,	end-after-100GB
sda5	: no-os,	64, nopakmgr,	no-docgrub,	nogrub,	nogrubinstall,	no-grubenv,	noupdategrub,	end-after-100GB
sda6	: is-os,	64, apt-get,	signed grub-pc grub-efi ,	grub2,	grub-install,	grubenv-ok,	update-grub,	end-after-100GB
sda7	: no-os,	64, nopakmgr,	no-docgrub,	nogrub,	nogrubinstall,	no-grubenv,	noupdategrub,	end-after-100GB

Partitions info (2/3): _________________________________________________________

sda1	: isnotESP,	part-has-no-fstab,	no-nt,	no-winload,	no-recov-nor-hid,	no-bmgr,	notwinboot, ntfs
sda2	: isnotESP,	part-has-no-fstab,	no-nt,	no-winload,	no-recov-nor-hid,	bootmgr,	is-winboot, ntfs
sda3	: isnotESP,	part-has-no-fstab,	no-nt,	haswinload,	no-recov-nor-hid,	bootmgr,	notwinboot, ntfs
sda5	: isnotESP,	part-has-no-fstab,	no-nt,	no-winload,	no-recov-nor-hid,	no-bmgr,	notwinboot, ntfs
sda6	: isnotESP,	fstab-has-goodEFI,	no-nt,	no-winload,	no-recov-nor-hid,	no-bmgr,	notwinboot, ext4
sda7	: is---ESP,	part-has-no-fstab,	no-nt,	no-winload,	no-recov-nor-hid,	no-bmgr,	notwinboot, vfat

Partitions info (3/3): _________________________________________________________

sda1	: not--sepboot,	no---boot,	part-has-no-fstab,	not-sep-usr,	no---usr,	part-has-no-fstab,	no--grub.d,	sda
sda2	: not--sepboot,	no---boot,	part-has-no-fstab,	not-sep-usr,	no---usr,	part-has-no-fstab,	no--grub.d,	sda
sda3	: not--sepboot,	no---boot,	part-has-no-fstab,	not-sep-usr,	no---usr,	part-has-no-fstab,	no--grub.d,	sda
sda5	: not--sepboot,	no---boot,	part-has-no-fstab,	not-sep-usr,	no---usr,	part-has-no-fstab,	no--grub.d,	sda
sda6	: not--sepboot,	with-boot,	fstab-without-boot,	not-sep-usr,	with--usr,	fstab-without-usr,	std-grub.d,	sda
sda7	: not--sepboot,	no---boot,	part-has-no-fstab,	not-sep-usr,	no---usr,	part-has-no-fstab,	no--grub.d,	sda

fdisk -l (filtered): ___________________________________________________________

Disk sda: 931.51 GiB, 1000204886016 bytes, 1953525168 sectors
Disk identifier: 0x5c010af7
     Boot      Start        End    Sectors   Size Id Type
sda1             2048   24578047   24576000  11.7G 27 Hidden NTFS WinRE
sda2         24578048   25192447     614400   300M  7 HPFS/NTFS/exFAT
sda3         25192448  434792447  409600000 195.3G  7 HPFS/NTFS/exFAT
sda4        434794496 1953525167 1518730672 724.2G  5 Extended
sda5        434796544 1922803711 1488007168 709.5G  7 HPFS/NTFS/exFAT
sda6       1922805760 1952808959   30003200  14.3G 83 Linux
sda7  *    1952811008 1953525167     714160 348.7M  c W95 FAT32 (LBA)
Disk sdb: 14.45 GiB, 15514730496 bytes, 30302208 sectors
Disk identifier: 0x0079b378
     Boot Start      End  Sectors  Size Id Type
sdb1  *     2048 30302207 30300160 14.4G  c W95 FAT32 (LBA)
Disk zram0: 1.91 GiB, 2049552384 bytes, 500379 sectors

parted -lm (filtered): _________________________________________________________

sda:1000GB:scsi:512:4096:msdos:ATA TOSHIBA DT01ACA1:;
1:1049kB:12.6GB:12.6GB:ntfs::msftres;
2:12.6GB:12.9GB:315MB:ntfs::;
3:12.9GB:223GB:210GB:ntfs::;
4:223GB:1000GB:778GB:::;
5:223GB:984GB:762GB:ntfs::;
6:984GB:1000GB:15.4GB:ext4::;
7:1000GB:1000GB:366MB:fat32::boot, lba;
sdb:15.5GB:scsi:512:512:msdos: USB DISK 2.0:;
1:1049kB:15.5GB:15.5GB:fat32::boot, lba;

blkid (filtered): ______________________________________________________________

NAME   FSTYPE   UUID                                 PARTUUID                             LABEL       PARTLABEL
sda                                                                                                   
├─sda1 ntfs     080EA3A60EA38B70                     5c010af7-01                                      
├─sda2 ntfs     C4A0A875A0A86F9A                     5c010af7-02                                      
├─sda3 ntfs     D626F56C26F54DCD                     5c010af7-03                                      
├─sda4                                               5c010af7-04                                      
├─sda5 ntfs     CEF450E9F450D575                     5c010af7-05                          DATA        
├─sda6 ext4     0318db25-e1bb-41fc-9c6e-0babbe63de9a 5c010af7-06                                      
└─sda7 vfat     32F3-F780                            5c010af7-07                                      
sdb                                                                                                   
└─sdb1 vfat     6EC5-95BD                            0079b378-01                          LUBUNTU 25_ 

Mount points (filtered): _______________________________________________________

                        Avail Use% Mounted on
/dev/sda1               11.6G   1% /mnt/boot-sav/sda1
/dev/sda2              264.3M  12% /mnt/boot-sav/sda2
/dev/sda3               73.8G  62% /mnt/boot-sav/sda3
/dev/sda5              395.1G  44% /mnt/boot-sav/sda5
/dev/sda6                6.2G  50% /mnt/boot-sav/sda6
/dev/sda7              341.9M   2% /mnt/boot-sav/sda7
/dev/sdb1               11.3G  22% /cdrom
efivarfs                25.4K  53% /sys/firmware/efi/efivars

Mount options (filtered): ______________________________________________________

/dev/sda1              fuseblk         rw,relatime,user_id=0,group_id=0,allow_other,blksize=4096
/dev/sda2              fuseblk         rw,relatime,user_id=0,group_id=0,allow_other,blksize=4096
/dev/sda3              fuseblk         rw,relatime,user_id=0,group_id=0,allow_other,blksize=4096
/dev/sda5              fuseblk         rw,relatime,user_id=0,group_id=0,allow_other,blksize=4096
/dev/sda6              ext4            rw,relatime
/dev/sda7              vfat            rw,relatime,fmask=0022,dmask=0022,codepage=437,iocharset=iso8859-1,shortname=mixed,errors=remount-ro
/dev/sdb1              vfat            ro,noatime,fmask=0022,dmask=0022,codepage=437,iocharset=iso8859-1,shortname=mixed,errors=remount-ro

========================== sda6/etc/fstab (filtered) ===========================

# <file system>             <mount point>  <type>  <options>  <dump>  <pass>
UUID=0318db25-e1bb-41fc-9c6e-0babbe63de9a /              ext4    defaults   0 1
UUID=32F3-F780                            /boot/efi      vfat    defaults   0 2
/swapfile                                 swap           swap    defaults   0 0

======================= sda6/etc/default/grub (filtered) =======================

GRUB_DEFAULT=0
GRUB_TIMEOUT_STYLE=hidden
GRUB_TIMEOUT=0
GRUB_DISTRIBUTOR='Ubuntu'
GRUB_CMDLINE_LINUX_DEFAULT='quiet splash'
GRUB_CMDLINE_LINUX=""

==================== sda6: Location of files loaded by Grub ====================

           GiB - GB             File                                 Fragment(s)
 923.528396606 = 991.631065088  boot/vmlinuz                                   1
 923.528396606 = 991.631065088  boot/vmlinuz-6.14.0-15-generic                 1
 923.528396606 = 991.631065088  boot/vmlinuz.old                               1
 923.437797546 = 991.533785088  boot/initrd.img                                4
 923.437797546 = 991.533785088  boot/initrd.img-6.14.0-15-generic              4
 923.437797546 = 991.533785088  boot/initrd.img.old                            4

===================== sda6: ls -l /etc/grub.d/ (filtered) ======================

-rwxr-xr-x 1 root root 18133 Apr 10 13:23 10_linux
-rwxr-xr-x 1 root root 43202 Apr 10 13:23 10_linux_zfs
-rwxr-xr-x 1 root root 14513 Apr 10 13:23 20_linux_xen
-rwxr-xr-x 1 root root   786 Apr 10 13:23 25_bli
-rwxr-xr-x 1 root root 13120 Apr 10 13:23 30_os-prober
-rwxr-xr-x 1 root root  1174 Apr 10 13:23 30_uefi-firmware
-rwxr-xr-x 1 root root   730 Mar 25 16:35 35_fwupd
-rwxr-xr-x 1 root root   214 Apr 10 13:23 40_custom
-rwxr-xr-x 1 root root   215 Apr 10 13:23 41_custom

===================== sda7/efi/ubuntu/grub.cfg (filtered) ======================

search.fs_uuid 0318db25-e1bb-41fc-9c6e-0babbe63de9a root hd0,msdos6 
set prefix=($root)'/boot/grub'
configfile $prefix/grub.cfg

====================== sdb1/boot/grub/grub.cfg (filtered) ======================

Try or Install Lubuntu
Lubuntu (safe graphics)
OEM install (for manufacturers)
Boot from next volume
UEFI Firmware Settings
Test memory

==================== sdb1: Location of files loaded by Grub ====================

           GiB - GB             File                                 Fragment(s)
            ?? = ??             boot/grub/grub.cfg                             1



Suggested repair: ______________________________________________________________

The default repair of the Boot-Repair utility would purge (in order to remove grub-efi) and reinstall the grub2 of
sda6 into the MBR of sda.
Grub-efi would not be selected by default because legacy Windows detected.
Additional repair would be performed: unhide-bootmenu-10s win-legacy-basic-fix

Confirmation request before suggested repair: __________________________________

LegacyWindows detected. The boot of your PC is in EFI mode. You may want to retry after changing it to BIOS-compatibility/CSM/Legacy mode.
Are you sure you want to continue anyway?

Final advice in case of suggested repair: ______________________________________


The boot files of [sda6 (end>100GB)] are far from the start of the disk. Your BIOS may not detect them. You may want to retry after creating a /boot partition (EXT4, >200MB, start of the disk). This can be performed via tools such as gParted. Then select this partition via the [Separate /boot partition:] option of [Boot Repair]. (https://help.ubuntu.com/community/BootPartition)Please set your BIOS in Legacy mode in order to start your Ubuntu 25.04, then type command [sudo update-grub] in order to add the Windows entry to your GRUB menu.

repair according this will install sda6 into MBR of SDA with grub instead of current installed grub-efi.

But problem is that your Windows does not use grub at all. You maybe need to set boot disk drive with direct Windows boot. If Windows 7 uses UEFI partition that it should have such boot option also as default, but Maybe YOUR Windows 7 uses only MBR boot with direct calling Windows 7.

Also If your disk is in MBR or GPT may cause problems… But that shouldn’t changed. UEFI or old CST lagacy boot for direct Windows 7 boot could may be solution with direct drive boot selected, but that in your case after repair would be grub(instead of current grub-uefi) and not Windows loader, which could be called after grub loaded, but cannot be told if successfuly.

some windows or mbr fix could may help, but don’t know if there is some Windows boot utility or if Windows Safe Boot options(maybe with premade boot disk) or some there Windows Safe Boot console fix attempt with some howto could help. MSFT should know what to do, but Lubuntu could also…

No, not yet, because you have a more fundamental issue:-

  • Windows 7 is installed in old-fashioned Legacy mode
  • Lubuntu is installed in UEFI mode

This will never work as a dual boot system.

Your first task is to backup all your personal data.

Then, decide if you want to continue to use unsupported Windows 7?

Is your PC a model from 2011 and unsuitable for Windows 11?
Lubuntu 24.04 should be ideal as a single OS.

As your PC is EFI compatible, any OS should really be installed in UEFI mode with GPT (partition table)

Thank you for your reply!

As this computer is mainly used for storage purposes, I believe that Windows 7 is sufficient for now. My priority is to get the PC into working condition and to make sure that the data will be safe. Would it be possible to install Lubuntu on a flash drive instead?

Since two drives, you technically can dual boot with Windows in very old BIOS/MBR mode and Lubuntu in UEFI boot mode. But may have to go into UEFI settings and change default boot mode from UEFI to BIOS or vice-versa to boot.

You can install the BIOS boot version of grub into sdb’s MBR, so both systems boot in BIOS mode. Do not install grub to Windows drive’s MBR. You can use Boot-Repair booted in BIOS mode to install the BIOS mode grub, but probably have to use advanced mode to choose sdb drive. Default is normally first drive & that would overwrite the Windows boot loader. While that works & grub should then offer to boot Windows any Windows issue will prevent grub from booting Windows & you have to directly boot it after restoring a Windows boot loader to sda.

You can install to an external drive. I have a full install on an external SSD in UEFI mode and had to add a BIOS boot of grub to 2006 laptop to boot that install, bypassing UEFI version of grub & directly booting. For older systems using an SSD makes a major improvement.

Thanks for the detailed explanation! Right now, I just need to restore Windows 7 to a bootable state. I’m not experienced with GRUB yet, could you provide step-by-step instructions to fix the Windows bootloader?

We do not support Windows. Since I stopped using Windows with XP, I lost most of my Windows experince. Now I do have laptop with dual boot and have to use Google or a Windows site to find ways to fix Windows, and most of those do not work as Microsoft moves things around. I prefer Linux terminal repairs as those work in all versions. Gui even in Linux changes, so older screenshots of repairs often do not match newer versions

But because old Windows in BIOS mode, Boot-Repair can do a few things. Boot-Repair is primarily for Linux, and Microsoft restricts use of its files, so open source cannot do much in the way of Windows repairs. Boot-Repair can restore an old BIOS mode boot of a open source boot loader to Windows MBR that works like Windows boot loader. But you may have to make sure UEFI/BIOS is set to boot in BIOS mode from sda drive. Report looked like you still have Windows boot loader, so may only need system settings changes.

Other repairs to Windows requires your Windows repair/recovery flash drive. And booted in old BIOS boot mode.
Do not know if still correct.
https://forums.techarena.in/guides-tutorials/1114725.htm

Still better not to use Windows 7 as obsolete. Only if not using Internet may you still safely use it.

1 Like

You mentioned two hard drives in post no. 1, but the boot-repair report only showed one internal disk (Toshiba) and one USB

sda:1000GB:scsi:512:4096:msdos:ATA TOSHIBA DT01ACA1
sdb:15.5GB:scsi:512:512:msdos: USB DISK 2.0

Where is the second hard drive?

It’s advisable to use Windows utilities to repair the Windows bootloader.

Yes, of course. You already have Lubuntu installer on your USB
Two more options:-

  • Lubuntu live with persistence
  • Lubuntu full install with user login and password

I missed that sdb was the USB flash drive.

With one drive, and old BIOS boot you can only have one boot loader in MBR. And grub is only one that will dual boot, but it only boots working Windows. So if Windows needs chkdsk, defrag or other repairs you have to use Windows tools.

So you need both the Ubuntu live installer to restore grub & Windows repair flash drive to fix Windows. Boot-Repair can install a Windows type boot loader, but if you want the Windows boot loader you need Windows repair/recover flash drive.

Use Boot-Repair to install grub to MBR of sda. It should offer to boot Windows, if Windows does not need any fixes. When Windows needs fixes you may need to restore a Windows boot loader, fix Windows and restore grub to MBR for dual booting.
can exist in
The advantage of UEFI is that all boot loaders can share one ESP if one drive. So when Windows needs fixes you often can directly boot Windows from UEFI/BIOS one time boot menu. Also gpt have many advantages over old MBR, but conversion from MBR to gpt will totally erase entire drive, so good backups required. Windows requires gpt with UEFI boot and requires MBR with BIOS boot.

I have installed many times to USB flash drives. Many were very slow. A few newer ones are a bit better but an external SSD if much better.