Recovery Guides: step-by-step DiskPatch operations:
FAT 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.
sector damaged/deleted, no partition access
appears as unformatted, "partition needs to be formatted",
"unknown file system", file system identified as RAW
the boot sector
|Things you need to know before we
- 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
key to abort or leave a menu.
- Pressing <Escape> at any time
during the repair will abort the repair and leave the disk
unchanged, with the exception of the FAT synchronize function: if
this has been initiated, aborting it WILL leave the disk in an
altered state. Use the undo to revert changes.
- 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
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
The selected disk will be marked in high intensity blue in the disk list (disk
0 in our
|Now select 'Perform repairs', then
'Rebuild boot sectors'.
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
at this point to skip creating the undo file (not recommended).
|A list of partitions is displayed.
Select the appropriate partition and press <Enter>.
|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:
depending on the type of problem this display will show different
results. In our example some values in the boot sector are incorrect,
which results in the screen as displayed above. If the boot sector was
deleted entirely (and filled with blanks) the screen would look
something like this:
Because no values are found if the
boot sector is completely wiped, some tests can not be run and will
display a result in yellow. These tests will be performed as soon as the
values that are needed have been determined (during the actual repair
phase); this should have no adverse effect on the repair.
|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 will not
affect the partition negatively but will be repaired if a repair is
In our example 'sectors per cluster' is incorrect, as is the total
number of sectors for this partition. These values must be corrected
before the partition can be accessed again. Press any key to exit the
|Now select 'Continue' to start the
repair. DiskPatch will perform the steps needed to recreate the boot
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.
Some of these steps may take some time, in which case a progress
bar is displayed:
|If all necessary data is found and
the repair can continue, the following display will appear:
|Note: selecting a directory
as root cluster is only needed when a FAT32 boot sector is being
repaired; this display will not appear if you're repairing a FAT16 or a
NTFS boot sector.
To rebuild a FAT32 boot sector, DiskPatch needs to locate the root
directory for that partition. If DiskPatch finds a candidate it will
display this sector as if it was a root directory. This will allow you
to determine whether DiskPatch picked the right sector or not. In our
example you can clearly see that this sector is the right one; the file
and directory names are the ones that were in the root directory before
the partition problems occurred.
If a sector is displayed that is obviously not the right sector, select
'Continue scanning'. If the currently displayed sector is the root
directory, select 'Select as root cluster'.
The repair will now continue. If the repair is completed successfully
the following completion screen will appear:
|If the 'Boot sector status' and
'FAT status' are both '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.
|The label for the partition is
changed to 'REPOMAN' to indicate that DiskPatch has rebuilt the boot
sector for that partition. You can change that later, when you have
access to the partition again.
|This completes the repair.