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How to Remove the EMBR from a Drive

Understanding the EMBR

The first sector (or block of data) on your hard disk is called the Master Boot Record (MBR). The MBR contains the partition table that defines the partitions (or areas) on your hard drive and a small program that transfers control to the first sector (boot sector) of one of the partitions.

The partition table can contain up to four primary partition entries that contain information on where the partition begins and ends, a flag to mark the active (or bootable) partition, and the type of file system used in the partition.

The Extended Master Boot Record (EMBR) specification dynamically extends the capabilities of the system. The EMBR contains a block of code, called the EMBR Loader, and three tables—one for partition information, one for boot file information, and one for information on drivers that may need to be loaded on your system. Each of these tables can contain up to 255 entries. The table in the EMBR that contains partition information is called the Master Partition Table (MPT). This table is used in place of the partition table to contain all partition information.

BootIt NG handles the MPT and partition table by letting you create bootable configurations (or boot items) allowing you to choose which partitions from the MPT are to be placed into the partition table.

The EMBR is automatically created on drives connected to the computer when BootIt NG is installed or updated. This includes both internal and external drives (e.g. USB, eSATA).

When BootIt NG is no longer being used with the drive or other partitioning software has been used on the drive, the partitions in the EMBR and the partition table may no longer be in sync. This can cause problems when using programs that look in the EMBR for partition information (e.g. Image for Windows).

In this case, the EMBR must be removed from the drive to allow the correct partitions to be found and used.

Note: More information on BootIt NG and the EMBR can found in the BootIt NG Manual.

 

Before you begin...

It may be helpful to make note of the positions, sizes, and types of the current partitions on the drive as displayed by the operating system (Windows, Linux, etc.). This information can then be used to verify that the correct partitions exist on the drive after the removal of the EMBR. TeraByte's free Partition Information utility (PARTINFG) can be used to obtain this information and save it to a file for easy reference. When using this program, note that the MBR view will display partitions in the MBR and the MPT view will display partitions in the EMBR.

Warning: Following the procedures below may result in changes to the partition table. There is the possibility of data loss if these changes are done incorrectly. Backing up any important data on the drive before proceeding is recommended.

Multiple methods to remove the EMBR are detailed below. Advanced users may wish to read through the entire article before selecting which method to use.

 

Removing the EMBR When the Partitions are Out of Sync

The easiest method to remove the EMBR when the partitions are out of sync with the partition table is to boot the BootIt NG media on a computer on which BootIt NG is not installed. In these cases, this usually isn't a problem as BootIt NG isn't being used. However, if a computer on which BootIt NG is installed must be used, you will need to follow the instructions in the next section below to manually remove the EMBR.

Caution: In most cases, the EMBR can be removed easily and safely, without causing the existing partitions (those in the partition table) to be lost. However, there are some configurations that require special steps to allow the safe removal of the EMBR. These are noted in the instructions below.

Instructions:

  1. This method requires BootIt NG to remove the EMBR. If necessary, download it and create the boot media (CD, USB flash drive, floppy).

  2. If the drive is external, make sure it's connected and powered on before booting into BootIt NG.

  3. Boot the computer into BootIt NG from the boot media.

  4. The following notice will be displayed:

    An EMBR was found on HD# with partitions that are different than the partitions in the MBR. You MUST choose to delete the EMBR IF this is a new installation of BootIt NG or the EMBR is out of date. Do you wish to delete this EMBR?
    [YES] [NO]

    Caution: If this notice is NOT displayed or an error message is displayed for the drive (e.g. BootIt was unable to read from an area of HD# which is required for proper operation.), please see the instructions in the next section below to manually remove the EMBR.

  5. Click the Yes button to remove the EMBR. The existing partitions will remain on the drive.

  6. Click the Cancel button to cancel the installation of BootIt NG.

  7. Click the Ok button to enter Maintenance Mode.

  8. Click the Partition Work button, select the drive which had the EMBR removed, and verify the partitions listed for the drive are correct. Note: The partition labels displayed may not be the same as those used by Windows. Do not rely solely on the label for verification -- use the position and size. Details on how BootIt NG handles volume labels can be found in this KB article.

  9. When finished, remove the BootIt NG boot media and reboot the computer.

The correct partitions should now be displayed by the operating system, BootIt NG, Image for Windows, Image for Linux, and Image for DOS.

 

Using BootIt NG to Manually Remove the EMBR

Instructions:

  1. This method requires BootIt NG to remove the EMBR. The procedure can be done from the installed version of BootIt NG or from the BootIt NG boot media. If necessary, download it and create the boot media (CD, USB flash drive, floppy).

  2. If the drive is external, make sure it's connected and powered on before booting into BootIt NG.

  3. Boot the computer into BootIt NG.

  4. Enter Maintenance Mode: From the installed version, click the Maintenance button on the Boot Menu. From the boot media version, click the Maintenance button on the Floppy Boot Menu (shown if BootIt NG is installed) or click Cancel on the Setup window and then Ok to enter Maintenance Mode.

  5. Click the Partition Work button on the desktop.

  6. Select the drive for which you need to remove the EMBR. Note that the drives may be listed in a different order than shown in Windows/Linux.

  7. Click the Undo EMBR button. The partitions shown for the drive will change to those stored in the EMBR.

  8. For each partition shown for the drive, do the following:
    • Select the partition.
    • Click the Delete button. Caution: Do NOT check either the Clear Boot Sector or Wipe Partition options.
    • Click Yes to delete the partition.

  9. Once all partitions have been deleted, select the Free Space entry and click the Undelete button. Click OK on the Undelete window.

  10. The drive will be scanned for deleted partitions. The amount of time taken depends on the size of the drive and the partitions found. In many cases, the scan completes quickly. The number of recovered partitions will be displayed when the scan has finished. Click Close.

  11. The undeleted partitions will now be displayed in the Partitions list.

  12. Verify the partitions listed for the drive are correct. Note: The partition labels displayed may not be the same as those used by Windows. Do not rely solely on the label for verification -- use the position and size. Details on how BootIt NG handles volume labels can be found in this KB article.

    If one or more partitions found are incorrect, do the following:
    1. Select the incorrect partition and click the Delete button.
    2. In the Delete window, check the Clear Boot Sector option. Do not check the Wipe Partition option.
    3. Click Yes to delete the partition.
    4. Select the Free Space item for the deleted partition and click the Undelete button.
    5. Click OK to run the scan.
    6. You may need to repeat these steps several times until the correct partition is found (deleting the Boot Sector of an incorrect partition prevents that partition from being found again when the next undelete scan is run).


The correct partitions should now be displayed by the operating system, BootIt NG, Image for Windows, Image for Linux, and Image for DOS.

 

Using a Disk Editor to Manually Remove the EMBR

Advanced users may prefer using a disk editor to edit a few bytes on the drive to remove the EMBR. If you are familiar with using a disk editor, this method is very quick and easy.

Instructions:

  1. Run the Disk Editor of your choice and bring up a HEX view of Sector 1 of the drive (note that this will be the second sector).

  2. The first four bytes of Sector 1 will be 45 4D 42 52 ('E', 'M', 'B', 'R').

  3. Change all four bytes to 0 (zero).

  4. Save the sector.

 

Using MBRWORK to Remove the EMBR

MBRWORK is a free utility provided by TeraByte. It allows you to reset the EMBR area of a drive.

Note: This program only works in DOS.

Instructions:

  1. Run MBRWORK.

  2. Change the active hard drive to select the correct drive (option 7).

  3. Reset the EMBR area of the drive (option 3).

  4. Exit the program.

 

Technical Notes:

Undelete does not find the first partition

BootIt NG uses the first track of the hard drive (sectors prior to 63) for the EMBR. As a result, undelete will not be able to find any partitions that start before Sector 63. Using an alternate program to undelete the partition will be necessary.

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