Ottawa PC Users' Group, Inc.
Good Disks Go Bad - Part 1
by Alan German
your external drive. Windows coughs and splutters, and
the dreaded - your disk is not accessible - message box
is displayed! This happened recently to a friend who is
an avid nature photographer. On her return from Uganda
she plugged in a 32 GB SDcard, nominally containing over
1000 photographs, and found that she was unable to access
any of the images.
what? Well one option, offered by the service department
of a big-box computer store was to hand over the memory
card and $300 and see if the files could be
recovered. Another option is the do-it-yourself solution.
Find some disk recovery software and use it to try to
recover the disks contents.
Now, while I am a huge fan of free software, the bad news
is that I am not aware of any such products that will
recover data from large-capacity disk drives. Sure, many
commercial packages offer trial versions to provide
recovery capability, but these always seem to be limited
to something like the first gigabyte of recovered files.
Addressing the needs of larger data recovery efforts
requires use of the full-blown package.
So, it may well be possible to use a trial version of
some data recovery software to check out the possibility
of accessing a corrupt drive, but it will almost
certainly be necessary to purchase the full commercial
package in order to recover all the data from the disk.
Fortuitously, for my friend, around the time of her issue
with the SDcard that had gone bad, I had been approached
by MiniTool to review their Power Data Recovery software.
Initially, I had declined to undertake the review since I
couldnt see how to meaningfully do so without
having a corrupted drive to work on. Clearly, my
friends SDcard provided the perfect candidate for a
real-world test of the program. So, armed with a licensed
copy of MiniTools Power Data Recovery software, I
was ready for the challenge.
Downloading and installing the software was simple and
straightforward. The programs main screen provides
access to a number of modules. My first choice was the
sub-program named Digital Media Recovery since this
seemed to be the most appropriate potential fix for the
SDcard in question.
recovery process brought up a dialogue box indicating the
progress of a scan of the SDcard and, most heartening, an
indication of the number of files that had been
recovered. Another useful feature of the display was an
indication of the likely time remaining to complete the
scan. Since this was of the order of 25 minutes, it was
obviously time to make a pot of coffee!
without me doing anything more than enjoying my coffee,
the display changed to advise me that 1030 files had been
recovered. The 24.91 GB of data comprised RAW digital
image files which were contained in a number of folders
and sub-folders. So, it appeared that both the individual
data files, and the file structure on the SDcard, had
been recovered. I was now able to select all the
recovered files and folders and save them permanently to
the hard disk on my computer. Success!
Flash Drive Recovery
The second test that I performed was to check the
Undelete Recovery module. In this case, I deleted all the
files from a USB flash drive. I copied a number of files
a selection of jpg, exe, docx, txt and pdf files
to a folder on my hard drive, and then copied the
files from this folder onto the USB drive. Then, I
deleted the files from the flash drive so that it was
nominally blank. Running the Undelete Recovery process
from the Power Data Recovery software very quickly
recovered the files on the USB drive.
Most of the files were restored to their original state
on the USB drive. A couple of files had the first
characters of their file names replaced with the
underscore character. This was not totally unexpected
since this character substitution is part of the process
by which Windows marks files as being deleted. Restoring
the original file names was simply a matter of renaming
the restored files (e.g. _SC_0184.JPG was renamed to
Once this process was complete, a bit-for-bit file
comparison, between the restored files on the USB drive
and the original files in the folder on the hard disk,
confirmed that the recovery process had been 100%
successful. Another triumph for Power Data Recovery!
The software developers indicate that the CD/DVD Recovery
module is designed specifically to recover lost and
deleted files from damaged, scratched or defective CD and
DVD disks. I happened to have a CD that was
refusing to open one of several hundred digital photos
that were backed up on the disk, and so I opted to try to
recover this specific file. The CD/DVD Recovery
modules operation was very similar to that of the
previously-used Undelete Recovery module. I chose to
conduct a Full Scan of the 698 MB CD. This took about
five minutes and identified a number of files and
folders. I selected the corrupted image file,
which displayed correctly in the preview window, and
saved it to Drive D: (the data partition on my hard
The only real issue was that, after having saved the
file, I couldnt immediately locate it on the hard
drive. It wasnt saved to the root of the disk,
rather it was stored as D:\ISO9660 &
Joliet\$Root1\MON_001\001.JPG which was clearly a
function of the original file system on the CD-ROM.
However, once I realized that the file had been saved to
a folder, it was simple matter to initiate a bit-for-bit
comparison between the recovered image and a copy of the
same file from a second backup on an external hard disk.
The recovered file proved to be identical to the backup
showing that Power Data Recoverys third module was
It turns out that I didnt actually need to scan the
CD, I could also have used the Open control button. For
my test CD, this listed a number of tracks and the
available files and folders on these tracks. Once again,
the file I wanted to recover was listed, displayed in the
preview window, and could be copied from the CD to my
The CD/DVD Recovery module includes support for ISO9660,
Joliet, and UDF formats, RAW files, and can process
multi-session disks. This can lead to a fairly complex
directory listing where, for example, my disk contained
listings for the same files and folders in different
sections (e.g. ISO9660 & Joliet ) or tracks (Track01,
Track02, etc.). The good news I that it didnt seem
to matter which listed file I chose to recover.
The other two modules in Power Data Recovery are Lost
Partition Recovery and Damaged Partition Recovery. Each
of these modules is applicable to the partition structure
of a hard drive. Using these modules is a little trickier
than those for flash drives and CD-ROMs so we will
leave this discussion for Part 2.
Recovery (US $89.00)
MiniTool Solution Ltd.
Vancouver, British Columbia
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Ottawa Personal Computer Users' Group (OPCUG), Inc.
3 Thatcher Street, Ottawa, ON K2G 1S6
opinions expressed in these reviews do not necessarily
represent the views of the OPCUG or its members.