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Events Leading to Problem: Tony had a 57 GB hard drive divided into two partitions. The first partition was allocated 18 GB and the second partition 39 GB. Both were NTFS formatted. The second partition was assigned the drive letter G and was used to stored over 5,500 important data files that took him a year to create. Tony's problem began when he ran out of disk space on drive G (the second partition). He bought a disk management utility that was supposed to be able to "merge" the two partitions into one. Towards the end of the merging operation, the disk utility program failed. Tony was left with both partitions. However, the files on the second partition just disappeared, and Tony panicked. Initial User Reaction: Tony bought a copy of File Scavenger and attempted to recover the data. File Scavenger was able to restore almost all the files. However, the contents of 90% of the files were corrupt. Tony then contact us. Troubleshooting Strategy: We do not ask users to send us hard drives. We send them data recovery tools with simple and clear instructions to execute the tools. We feel this provides many advantages over conventional methods:
Resolution: Our technical staff were initially puzzled by the fact that most of the files were corrupt even though Tony had not written any new data to the second partition. We became suspicious of the disk utility. On an NTFS partition, information about a file is stored in a Master File Table (MFT) entry, including the filename, dates, etc. Most importantly, it contains pointers to the location on the disk of the actual data blocks. The pointers are offsets of the data blocks from the beginning of the partition. In this case it was the second partition. We discovered that as part of the merging operation, the disk utility had modified the pointers so the offsets would be computed from the beginning of the first partition. However, because the second partition was never merged successfully into the first partition, its MFT entries then contained incorrect offsets. (Except for the 10% or so of files that had not been modified.) After our analysis, we sent Tony a special copy of File Scavenger and instructions to force the program to use the first partition as the origin of all offsets. Amazingly, it worked! Tony was able to recover about 70% of his files. The others were corrupted during the partition merging process. At the time of this writing, Tony was still sorting through his files to validate the contents. User's Comments:
"...recovery has improved from 10% of 5000 files to 70%."
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