FTK Imager Alternative Free with Resume

FTK Imager is the most widely used free forensic disk imaging tool. It has been the default choice for examiners for over a decade. It produces E01 and raw images. It includes a file system browser and memory capture. It works.

But FTK Imager does not support resumable imaging. If a 4TB drive imaging session fails at 90% due to a USB disconnect, power loss or system crash, you start over from byte zero. The partial image is abandoned. Hours of acquisition time are lost.

For small drives, this is an inconvenience. For 4TB, 8TB and 12TB drives that are now common in forensic casework, it is a serious operational problem. A single failed 8TB acquisition can cost an examiner an entire day of lost work. Multiply that across a busy forensic lab handling dozens of cases per month and the lost productivity is significant.

Until now, resumable forensic imaging on Windows required X-Ways Forensics ($1,200+) or EnCase ($3,500+/year). Linux users had ddrescue, which resumes but produces raw output only with no GUI and no chain of custody documentation. There was no free Windows tool that combined resume, E01 output and chain of custody in one package.

Sherlock Forensics Disk Imager fills that gap.

Other tools have resume. ddrescue has had it for years. X-Ways and EnCase have had it for years. We are not claiming to invent resumable imaging. We are claiming to be the first tool that delivers all of the following in one free package:

Free (no license, no subscription, no trial)

Not $1,200 like X-Ways. Not $3,500/year like EnCase. Free forever with no feature restrictions.

Resumable imaging

If imaging is interrupted by power loss, USB disconnect or system crash, resume from the last successfully written sector. Not available in FTK Imager or Guymager.

E01 output format

Standard Expert Witness Format compatible with EnCase, FTK, X-Ways, Autopsy and Magnet AXIOM. Not available in ddrescue.

Chain of custody documentation

Automated imaging log with source drive identification, examiner name, timestamps and three SHA-256 hash values. Not available in ddrescue or Guymager.

Windows GUI

Native Windows application with a graphical interface. Not a Linux CLI tool that requires terminal experience.

Three-pass SHA-256 verification

Source hash, destination hash and source re-read hash. Detects transient drive errors that two-pass verification misses.

No other free tool on any platform combines all six of these capabilities.

Honesty about limitations is a sign of competence. Sherlock Forensics Disk Imager is a focused tool. It does one job: forensic disk imaging with resume and verification. Here is what it does not do.

Sherlock Forensics Disk Imager maintains a resume manifest file alongside the forensic image during acquisition. The manifest records the source drive serial number, the imaging format, the last successfully verified sector offset and a running SHA-256 computation state. The manifest is written to disk after every 512 MB checkpoint.

When imaging is interrupted for any reason, the partial image and manifest remain on the destination drive. When the examiner relaunches Sherlock and selects the same source and destination, the tool detects the existing partial acquisition. It verifies the integrity of completed data against the manifest, confirms the source drive serial number matches and offers to resume from the last checkpoint.

For E01 format, resume operates at segment boundaries. Each E01 segment is self-contained with internal CRC checksums. Sherlock verifies all completed segments before continuing. For raw dd format, resume uses sector-level tracking with 512 MB checkpoint granularity.

The resume mechanism works across power cycles and system restarts. Because the manifest is flushed to disk at every checkpoint, even an abrupt power loss preserves the resume state. The maximum data loss from an unclean interruption is 512 MB, the distance between checkpoints. Compare this to FTK Imager where any interruption loses the entire acquisition.

For context on how resume integrates with the broader forensic workflow, see our chain of custody documentation. The resume manifest becomes part of the chain of custody record, documenting any interruptions that occurred during acquisition.

Courts evaluate forensic methodology rather than tool brand or price. A free tool that produces proper SHA-256 hashes, complete chain of custody documentation and reproducible results meets the same evidentiary standards as a $3,500/year commercial platform.

Under the Daubert standard, admissibility of forensic evidence depends on whether the methodology is scientifically valid, whether it has been tested and whether it produces reliable results. Bit-for-bit disk imaging with SHA-256 hash verification is a well-established forensic methodology accepted by courts worldwide. The tool used to perform the imaging is less important than the methodology followed and the documentation produced.

Sherlock Forensics Disk Imager produces the documentation elements courts require: source drive identification, write protection verification, complete imaging parameters, SHA-256 hash values with timestamps and examiner identification. For additional guidance on forensic tool validation, refer to the NIST Computer Forensics Tool Testing Program and SWGDE best practices.