Recovery Guides: step-by-step DiskPatch operations:
NTFS Boot Sector repair.

A list of terms used in this page and their explanation can be found here.

This guide describes a DiskPatch function in condensed form: if you need additional information, read the corresponding part of the manual.

Problem boot sector damaged/deleted, no partition access
Symptoms partition appears as unformatted, "partition needs to be formatted", "unknown file system", file system identified as RAW
Solution rebuild the boot sector
Things you need to know before we start:
  • In the world of disks and data recovery we start counting disks at 0 (zero). So the first disk is 'disk 0', the second disk is 'disk 1', etc.
  • If you use the bootable CD/DVD you will need to find a target location for the files that DiskPatch creates when it's running; they can't be saved to the CD/DVD. You will either need a FAT formatted partition somewhere that can hold the files, or you can use a FAT formatted USB stick/key or USB disk to receive the files (read more here on how to prepare a USB key). DiskPatch will ask you where to save the files if the files can not be saved to the current location.
  • Use the cursor keys to navigate the menus, use the <Enter> key to select an option, use the <Escape> key to abort or leave a menu.
  • Pressing <Escape> at any time during the repair will abort the repair and leave the disk unchanged.
  • By performing this operation until this step, you can check the validity of the boot sector.
  • If you're using the trial version you can run this repair to completion; nothing is saved to disk when using the trial version. Use this to get an idea about whether the boot sector can be rebuilt.

Here we go:

Start DiskPatch and select the problem disk.

example: your screen will differ. Find more information on how to select a disk here.

After selecting the disk, the menu will expand, showing actions that can be performed for the selected disk.
The selected disk will be marked in high intensity blue in the disk list (disk 1 in our example).

Now select 'Perform repairs', then 'Rebuild boot sectors'.
DiskPatch will ask you if you wish to create an undo file (recommended), if this option is enabled.
Enter a description or leave the default suggested text. Press <Escape> at this point to skip creating the undo file (not recommended).

A list of partitions is displayed. Select the appropriate partition and press <Enter>.
Note that the volume label for the damaged partition is not displayed; this is caused by the fact that the boot sector damage keeps DiskPatch from finding the volume label on the partition.

The following menu is displayed:

Select 'Check and Fix Boot sector'. The other options are not relevant at this time and will be explained in other parts of the guides.
DiskPatch will now analyze the partition. 
The 'Repair partition' display shows the progress for the current analysis/repair.
A number of things are checked during the 'boot sector repair' operation. If the result is okay, 'done' will be displayed in green. If problems are found for that particular test, 'done' will be displayed in red. If a result could not be determined (because not enough data was found to make a reliable estimate) the result of the test will be displayed in yellow.
When the analysis is complete the following menu is displayed:

This menu allows you to enable or disable repairs. If repairs are needed, DiskPatch will have set the appropriate repair option to 'yes'. If no repairs are needed, all repair options are set to 'no'.
As you can see, in our example there's something wrong with this boot sector. Select 'View analysis details' if you wish to see more:

Severe problems (that require repair) are displayed in red. Problems displayed in yellow (not found in our example) will not affect the partition negatively but will be repaired if a repair is started.
In our example 'total sectors' is incorrect, which affects a number of other values. DiskPatch recognizes this and displays these in red as well. In addition, the 'media descriptor' value is incorrect. All these values must be corrected before the partition can be accessed again.
Note that if the boot sector had been wiped completely (or filled with garbage data) the 'View analysis details' display would show all zeros (or nonsense values).
Press any key to exit the 'details' display.

Now select 'Continue' to start the repair.

If you're using the trial version DiskPatch will not save any changes to disk, so it's safe to let this repair run to completion. This is actually a 'feature' of the trial version; this way you'll get an idea if things can be fixed.

The following display is shown:

DiskPatch now needs to determine the size of the clusters for this partition. You can let DiskPatch determine this automatically (recommended) or, if you know the value for 'clusters per sector', you can select the correct value yourself. The advantage of selecting the value yourself is that it will save some time (DiskPatch won't have to scan the partition to find the correct value). The advantage of selecting 'Determine automatically' is that the resulting value is very reliable; you can be pretty sure that DiskPatch finds the correct value. If, for whatever reason, DiskPatch fails in finding the correct value you can still try selecting a value manually.
For our example we'll select 'Determine automatically'. DiskPatch will now start the cluster analyzer:

Finding the correct value for 'sectors per cluster' may take some time. If you feel that after some scanning DiskPatch has found the correct value you can skip the rest of the scan by pressing the spacebar. BUT, the longer DiskPatch is allowed to scan, the more reliable the result: don't skip the rest of this analysis after a minute or so, it's best to let the scan run to at least 30%. Letting the scan run to completion can do no harm, so be patient.
When the cluster size has been determined the following display is shown:

At this point the MFT (master file table) is being located. This could take quite some time, as the entire partition must be searched. If DiskPatch fails to find the MFT you will be notified.
Once the MFT has been located a completion screen will be displayed:

If the 'Boot sector status' is 'Ok', the repair has been completed successfully.
Press a key to leave this display, you will be returned to the 'select partition for repair' display.
Note that the volume label is now found; the repaired boot sector allows DiskPatch to find the volume label on the partition.

This completes the repair.