Image your system with free Macrium


  1. Posts : 16,163
    7 X64
       #1251

    Paragon has an option to skip bad sectors, tho I haven't needed to use it. No idea if it is in the free version.
      My Computers


  2. Posts : 264
    Windows 7 Ultimate 64 bit SP1 x64
       #1252

    The presence or absence of VSS has absolutely no effect upon accessing a file that is stable and accessible and not "protected" by Windows.

    There is a world of difference between :-
    a corrupted file which has had some sectors totally over-written;
    and a corrupted sector which has had a few '1' bits fade into '0' bits (or vice versa) and cause the HDD controller to detect a HDD CRC error.

    Google gave 42,000 results for
    HDD CRC error
    e.g.
    CRC error on hard drive - is it toast? - AnandTech Forums
    How to Fix a Cyclic Redundancy Check Error: 9 Steps - wikiHow

    If your problem is CRC errors within sectors the "normal" best that you can hope for is to obtain the data with 30% worn out '1' bits and probable mistakes,
    BUT you cannot save that data to a file or to a clone with similar 30% worn out bits - they will be saved as absolute zeros and ones and the Sector CRC's will validate the contents of the sector.

    I do not know if by default an HDD controller will deliver data which it knows is corrupt.
    You would probably need the special software and hardware of a Data Recovery specialist to access data which the controller knows as corrupt.

    If Live Windows refuses to accept CRC corrupted data from the HDD, so would a bootable WinPE.
      My Computer


  3. Posts : 4,049
    W7 Ultimate SP1, LM19.2 MATE, W10 Home 1703, W10 Pro 1703 VM, #All 64 bit
       #1253

    alan10 said:
    If your problem is CRC errors within sectors the "normal" best that you can hope for is to obtain the data with 30% worn out '1' bits and probable mistakes,
    BUT you cannot save that data to a file or to a clone with similar 30% worn out bits - they will be saved as absolute zeros and ones and the Sector CRC's will validate the contents of the sector.
    That makes sense. :)
    I wouldn't expect cloning to duplicate a head crash on a HDD.

    I used "CRC on floppies", as an example, because I have encountered that issue.
    There were no error messages about CRC errors (only VSS).

    Do SSDs even use CRC?
    I would've expected them to use something better/different/newer.

    What is interesting is that his Windows install still functions (apart from his Adobe software, System Restore and Windows Update).

    alan10 said:
    I do not know if by default an HDD controller will deliver data which it knows is corrupt.
    You would probably need the special software and hardware of a Data Recovery specialist to access data which the controller knows as corrupt.
    I suspect that is true of SSDs too. :)
      My Computer


  4. Posts : 264
    Windows 7 Ultimate 64 bit SP1 x64
       #1254

    Two more reasons to consider Forensic worthless, and likely to make things worse not better.

    1.
    A forensic backup will attempt to read not only the sectors that hold existing files,
    but also all "free space" which is the sectors that held files that have since been deleted plus the sectors that have never been written to.

    My System C:\ has 41.9 GB free out of 55.7 GB.
    To copy or clone non-forensic requires the reading of only 13.8 GB
    To copy or clone forensic requires the reading of the entire 55.7 GB
    If there are two bad sectors in 55.7 GB there is only a 50% chance of one error in 13.8 GB,
    so a 50% chance of a perfect backup.

    Putting it another way, I am four times as likely to suffer a CRC ERROR ABORT were I to use the forensic mode.

    2.
    If this is an SSD and TRIM is enabled then at some time after a file is deleted Windows will tell the SSD that the sectors that held it are no longer in use.
    Either immediately or later ( I do not know and possibly depending upon each SSD vendor's design ),
    if you attempt to read those sectors you just possibly might be lucky,
    but it might simply give back random garbage or solid zero's or solid one's,
    and at some time when the SSD has nothing better to do - or when it is desperately short of clean Flash Cells,
    the SSD firmware will select a block of LBA designated Flash cells and relocate any live data to another block of Flash Cells and then erase the entire block of flash cells that now hold only deleted data or relocated data,
    after which I predict that no data recovery utility will be able to access what was deleted

    Conclusion :-
    Capturing data from Free space on an SSD is as reliable at showing the past,
    as Sacrificing a goat and studying its entrails to determine the future.

    You are correct about SSD's not depending upon CRC which can only detect errors.
    SSD's use ECC which incorporates significantly more overhead to facilitate correction on the fly
    https://en.wikipedia.org/wiki/ECC_memory

    I went into serious panic mode when looking at my SSD Smart data and :-
    I saw 25,000,000 UNCorrectable errors as the C:\ partition was imaged,
    That caused my to start this topic :-
    Errors in Flags and descriptions of Smart Data ? Hard Disk Monitoring

    You may get very valuable information from posts that are on that forum,
    and you will probably also get valuable answers to your own questions even if you only use a free trial.

    I am sorry, but I in my previous posts I had not recognised that you were dealing with an SSD and not an HDD.

    Regards
    Alan
      My Computer


  5. Posts : 4,049
    W7 Ultimate SP1, LM19.2 MATE, W10 Home 1703, W10 Pro 1703 VM, #All 64 bit
       #1255

    No problems


    alan10 said:
    I am sorry, but I in my previous posts I had not recognised that you were dealing with an SSD and not an HDD.
    No problems (and thanks for that link). :)

    I've missed information in people's posts before.
      My Computer


  6. Posts : 24,479
    Windows 7 Ultimate X64 SP1
       #1256

    lehnerus2000 said:
    I've missed information in people's posts before.
    Now you've earned your stripes Peter.
      My Computer


  7. Posts : 70
    Win 7 Pro 64 bit
       #1257

    Not sure if it's relevant, but I wanted to restore to an earlier image the other other day when investigating an issue that seemed to be related to a recent update to my graphics driver. Last month I made two images of my (OS-containing) SSD, one just an image, the other, an entire clone of the disk. I haven't tried making, then restoring, an entire disk clone before, and when I tried, I just got an error, I can't remember what it said, and Macrium wouldn't restore the clone. Thankfully I'd made an image a few days later and that restored fine. I have now deleted the 230GB cloned image as it was sitting uselessly on my secondary drive so can't go back to see why it wouldn't restore. I wonder if there's a moral there for someone?
      My Computer


  8. Posts : 10,796
    Microsoft Windows 7 Home Premium 64-bits 7601 Multiprocessor Free Service Pack 1
       #1258

    Diddlededum said:
    Not sure if it's relevant, but I wanted to restore to an earlier image the other other day when investigating an issue that seemed to be related to a recent update to my graphics driver. Last month I made two images of my (OS-containing) SSD, one just an image, the other, an entire clone of the disk. I haven't tried making, then restoring, an entire disk clone before, and when I tried, I just got an error, I can't remember what it said, and Macrium wouldn't restore the clone. Thankfully I'd made an image a few days later and that restored fine. I have now deleted the 230GB cloned image as it was sitting uselessly on my secondary drive so can't go back to see why it wouldn't restore. I wonder if there's a moral there for someone?
    Strange story. Why are you talking about "image" and "restore". A disk or partition that you did clone can be imaged, or cloned again (for example back to original disk). It confuses people if you use the wrong words.

    Without error message we can't help you I think
      My Computer


  9. mjf
    Posts : 5,969
    Windows 7x64 Home Premium SP1
       #1259

    Accepting that some people want to use the Macrium clone capability, it may be useful to document any potential problems.
      My Computer


  10. Posts : 24,479
    Windows 7 Ultimate X64 SP1
       #1260

    I wasn't confused at all.
      My Computer


 

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