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Cloned ssd not bootable

Hello. I just used Partition Assistant to clone my hdd (MBR) to an internal ssd (GPT). The cloning was successful, according to the program, but my pc will not boot from it. It's visible in BIOS as installed, but not as a bootable device. I switched from CSM to UEFI and removed the old hdd, but those things didn't work. Should I reclone and try again?


  • edited May 5
    "used Partition Assistant to clone my hdd (MBR) to an internal ssd (GPT)".
    Before cloning, please make sure that your source and target disk both have the same partition table type MBR/GPT. If your source disk is MBR, you could manually convert target disk to MBR, or you could use PA > Disk Clone with Exact-Sector-By-Sector setting, that will force the target disk to convert to MBR, but it will take longer.
    "I switched from CSM to UEFI"
    Please keep your motherboard mode the same, clone the disk, and boot target disk successfully. Then you could change modes or settings. Safer to do 1 thing at a time.
    It sounds like your source disk was MBR, and booted using UEFI-CSM. Keep those the same for your target disk, for successful boot. Then later you could change the settings if you want.
    When migrating Windows to a new disk or PC, it is best to use
    Backupper > System Backup with universal restore setting > restore disk, or Partition Assistant > MigrateOS.
    But this is not required. Disk Clone method is usually used for data-disks that do not have Windows, or for system-disks that do have Windows, but are complex. For most Windows migrations, such as yours, Auraelspeth, it is best to use BU > system clone/backup, or PA > MigrateOS.
    Please reply with a screenshot of your disks from Partition Assistant.
    Backupper WinPE USB:
    Add custom drivers, such as NVMe, if necessary. Does not work on some Monitors.

    Partition Assistant WinPE USB:
    Add custom drivers, such as NVMe, if necessary.

    Aomei (Win)PE Builder USB:
    Best for PCs before 2020, includes Partition Assistant, Backupper, Recuva, 7zip, OSF Mount, CPU-Z, Bootice, DiskMgmt.msc. Supports x64 portable apps. Does not support any additional drivers, such as some internal M.2 NVMe disks.
    Partition Assistant Manual

    Partition Assistant General Help Topics
    Free tool not from Aomei:
    Supergrub 2 - Force Boot Absolutely Anything

  • Thank you aiArtisan. You gave me lots of info I couldn't find anywhere else! Did not know about "make sure that your source and target disk both have the same partition table type MBR/GPT" so I'm sure that was an issue.

    After learning that, I converted the hdd to GPT, then recloned and again the ssd shows up in BIOS as installed but not a boot option. However, I was able to do a boot override using it, but I don't want to do that every time I start my pc.
  • Try running msconfig. On the boot tab, you should see every disk that Windows thinks is bootable, and the option to pick one as default.
  • edited May 6
    "the ssd shows up as installed but not a boot option"
    The hard drive partition table type-MBR/GPT must match the motherboard mode to boot.
    MBR > Legacy-BIOS or UEFI-CSM
    GPT > UEFI-nonCSM
    UEFI-CSM mode was created only as a transitional mode so old hard drives that used the old partition table type MBR could still use the newer motherboards. If you want to boot a disk that has GPT, you should disable UEFI-CSM mode, boot using UEFI-nonCSM.
    Also, as user Wssddc pointed out, if you are dual booting 2 Windows installations, it is usful to use
    Cmd > Msconfig
    to manage dual Windows boot settings.
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