Case Study: Recovery from Accidental Dynamic Disk Conversion & Obscured Partition Table
Client Profile: User of a new Toshiba laptop with an external hard drive.
Presenting Issue: Drastic, unexplained reduction in reported drive capacity (to 32GB) and complete invisibility of original user data, replaced by empty folders with anomalous naming conventions.
The Fault Analysis
The client’s description of a suddenly reduced capacity and inaccessible data, immediately following the creation of a recovery disk, pointed directly to a fundamental alteration of the disk’s partitioning scheme. Our diagnostics at Bracknell Data Recovery’s laboratory confirmed the hypothesis: the Windows recovery disk creation utility had inadvertently—and without explicit user warning—converted the basic disk to a Dynamic Disk.
This is a critical change in how the Windows operating system manages volumes. A Basic Disk uses a standard partition table (either MBR or GPT) to define simple primary and extended partitions. A Dynamic Disk, however, uses a proprietary Logical Disk Manager (LDM) database, stored in a 1MB region at the end of the disk, to manage volumes that can span multiple disks or be reconfigured on the fly.
The client’s original data remained physically intact on the disk. However, the LDM had overwritten the original partition table. The 32GB capacity the client could see was, in fact, a small, newly created LDM Metadata Partition containing the dynamic disk configuration data. The “strange computer writing marks” on the folders were artefacts of the file system trying to interpret LDM metadata structures as directory entries.
The Bracknell Data Recovery Solution
This was a classic case of logical partitioning damage requiring precise reconstruction of the original disk geometry.
Phase 1: Forensic-Level Disk Imaging & LDM Interrogation
The external HDD was connected to our DeepSpar Disk Imager to create a forensically sound, sector-by-sector image. This ensured all subsequent recovery work was performed on a copy, preserving the original evidence. Our engineers then used ACE Laboratory’s PC-3000 with its specialised LDM parsing modules to interrogate the dynamic disk metadata.
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We located the LDM Database at the end of the disk and decoded its internal structures to understand the new virtual disk layout.
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Crucially, this analysis confirmed that the conversion process had not overwritten the user’s original data partitions; it had merely made them inaccessible by superseding the original partition table.
Phase 2: Original Partition Table Reconstruction
The core of the recovery involved manually rebuilding the client’s original GUID Partition Table (GPT), which we presumed was in use given the drive’s 750GB capacity.
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Signature Scanning: We performed a low-level scan of the entire disk image, searching for known file system signatures. The original user data partition was quickly identified by locating the NTFS Signature (
EB 52 90 4E 54 46 53) at its expected offset, typically in sector 0 or 63 for the first volume. -
Parameter Calculation: Using the located NTFS boot sector, we extracted the $MFT (Master File Table) starting cluster and the total sector count for the original partition. The $MFTMirr location was also verified to cross-reference file system integrity.
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GPT Header & Entry Array Restoration: We scripted a tool to generate a new Protective MBR and a valid GPT Header, populating it with the correct disk GUID, a pointer to the partition entry array, and its CRC32 checksum. The partition entry array was then rebuilt, defining a single, healthy primary partition of the full 750GB capacity, starting at sector 2048 (the standard offset to avoid legacy MBR issues) and ending at the disk’s physical limit.
Phase 3: Validation and Data Extraction
The reconstructed GPT was written to a new, sanitised destination drive. This drive was then connected to a secure workstation.
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Mounting and Integrity Check: The operating system immediately recognised the drive with its correct capacity and a single, healthy NTFS volume. The volume mounted without errors.
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File System Traversal: We performed a full CHKDSK in read-only mode, which reported a clean file system with no lost clusters or cross-linked files, confirming the accuracy of our partition geometry reconstruction.
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Data Verification: The client’s original directory structure and files were fully accessible. We performed spot checks on files of various types (documents, archives, images) by verifying their internal headers and checksums against the file records in the $MFT, confirming 100% logical integrity.
Conclusion
The client’s data loss was not due to deletion or overwriting, but to an obscuration of the partition table by the Windows Dynamic Disk LDM. Standard data recovery software, which operates within the confines of the existing partition table, would have been ineffective. Our success was achieved by working beneath the operating system, using forensic techniques to manually locate and reconstruct the original disk geometry, thereby rendering the user’s data perfectly accessible once more.
The recovery was completed with a 100% success rate, returning all original data with its complete folder structure and file integrity intact.
Bracknell Data Recovery – 25 Years of Technical Excellence
When partitioning errors and complex logical failures occur, trust the UK’s No.1 HDD and SSD recovery specialists. We resolve the data loss scenarios that confuse standard utilities and other labs.