A Practitioner's Perspective
We test PST viewers because we use them. Sherlock Forensics processes PST files weekly for litigation support, internal investigations and regulatory compliance matters. We built Sherlock PST Viewer because no existing tool met our forensic requirements at a reasonable price point.
This comparison is honest. We note where competing tools outperform ours and where our tool falls short. Every tool on this list has a legitimate use case. The goal is to help you pick the right one for your situation.
Quick Comparison Table
| Tool | Price | Forensic Hashing | Chain of Custody | PST + OST | Batch Export | Best For |
|---|---|---|---|---|---|---|
| Sherlock PST Viewer Free | $0 | No | No | Yes | No | Quick PST viewing |
| Sherlock PST Viewer Pro | $67 USD | SHA256 | Yes | Yes | Yes | Forensic analysis |
| SysTools PST Viewer Pro | $299 USD | No | No | Yes | Yes | PST conversion |
| Kernel PST Viewer | $79 USD | No | No | PST only | Yes | PST recovery |
| FTK (Forensic Toolkit) | $3,000+ USD | Yes | Yes | Yes | Yes | Full forensic suite |
| Microsoft PST Viewer | $0 | No | No | PST only | No | Basic viewing (deprecated) |
| Free OST Viewer | $0 | No | No | OST only | No | Quick OST viewing |
1. Sherlock PST Viewer (Free / $67 Pro)
Publisher: Sherlock Forensics (Vancouver, BC)
Platform: Windows 10/11
Full disclosure: we built this tool. We include it in the comparison because excluding our own product from an honest comparison would be dishonest. We will note both strengths and weaknesses.
Strengths
- Read-only access by design. The tool cannot modify the source PST file.
- SHA256 per-message hashing in Pro edition. No other tool under $3,000 offers this.
- Automated chain of custody report generation in Pro edition.
- Opens both PST and OST files without Outlook installed.
- One-time purchase. No subscription. No annual renewal.
- Built by forensic examiners (CISSP, ISSAP, ISSMP) with 20+ years of court testimony.
Weaknesses
- Windows only. No macOS or Linux version.
- Newer tool with a smaller user base than established competitors.
- No PST-to-MBOX or PST-to-PDF conversion (planned for future release).
- Free edition lacks forensic features. You need Pro ($67) for court-grade output.
Best For
Forensic examiners, litigation support professionals and law firms that need court-admissible PST analysis without paying $3,000+ for a full forensic suite. The Free edition is useful for IT staff who need to view PST contents without Outlook.
2. SysTools PST Viewer Pro ($299 USD)
Publisher: SysTools Software
Platform: Windows
Strengths
- Mature product with a large user base and extensive documentation.
- PST to multiple format conversion (MBOX, EML, MSG, PDF, HTML).
- Handles large PST files (50GB+) reliably.
- Calendar, contact and task viewing alongside emails.
- Batch processing for enterprise deployments.
Weaknesses
- No forensic hashing of individual messages.
- No chain of custody report generation.
- Not designed for forensic analysis. Positioned as an IT/migration tool.
- $299 USD for a tool that lacks forensic features available in Sherlock Pro at $67.
- Annual subscription model for some editions.
Best For
IT administrators migrating from Outlook to other platforms. Organizations that need bulk PST-to-MBOX conversion. Not suitable for forensic analysis or litigation support due to lack of integrity verification.
3. Kernel PST Viewer ($79 USD)
Publisher: Kernel Data Recovery
Platform: Windows
Strengths
- Strong PST recovery capabilities for corrupted files.
- Reasonable price point at $79 USD.
- Recovers deleted items from damaged PST files.
- Preview functionality before export.
- Multiple export formats.
Weaknesses
- No forensic hashing.
- No chain of custody documentation.
- PST only. Does not open OST files in the base product.
- Recovery-focused rather than analysis-focused.
- Upsell to higher tiers for additional features.
Best For
Data recovery professionals who need to extract emails from corrupted or damaged PST files. Not a forensic analysis tool.
4. FTK / Forensic Toolkit ($3,000+ USD)
Publisher: Exterro (formerly AccessData)
Platform: Windows
Strengths
- Comprehensive forensic suite with PST parsing as one of many capabilities.
- Full hash verification and chain of custody.
- Accepted and recognized in courts worldwide.
- Processes PST files within the context of full disk forensic analysis.
- Enterprise case management and review features.
Weaknesses
- Starts around $3,000 USD with annual licensing.
- Massive overkill if you only need PST analysis.
- Steep learning curve. Designed for certified forensic examiners.
- Resource-intensive. Requires significant hardware.
- Annual subscription model increases long-term cost.
Best For
Forensic labs and law enforcement agencies that need a comprehensive forensic platform. If you already own FTK, use its PST capabilities. If you only need PST analysis, FTK is far more tool and cost than necessary.
5. Microsoft PST Viewer (Free / Deprecated)
Publisher: Microsoft
Platform: Windows
Strengths
- Free.
- Opens PST files without Outlook installed.
- Simple interface for basic viewing.
Weaknesses
- Deprecated. Microsoft has not updated this tool since 2018.
- Does not support Unicode PST files created by Outlook 2010 and later.
- No search functionality.
- No export capability.
- No forensic features of any kind.
- May not open PST files larger than 4GB.
- Increasingly difficult to find a legitimate download source.
Best For
Nothing in 2026. This tool is effectively abandoned. If you need a free PST viewer, use the Sherlock Free Edition instead. It handles modern PST files, provides full-text search and is actively maintained.
6. Free OST Viewer (Free)
Publisher: Various third-party developers
Platform: Windows
Strengths
- Free.
- Opens OST files without Exchange connectivity.
- Simple interface for basic viewing.
Weaknesses
- OST files only. Does not open PST files.
- No forensic features.
- Limited export options.
- Multiple versions from different publishers with varying quality.
- Some versions bundle adware or unwanted software.
- No hash verification or integrity checking.
Best For
IT staff who need quick access to orphaned OST files when the Exchange server is unavailable. Not suitable for forensic or legal purposes.
Winner by Use Case
- Best free PST viewer
- Sherlock PST Viewer Free. Modern, maintained, opens PST and OST files with full-text search. No Outlook required.
- Best forensic PST viewer (value)
- Sherlock PST Viewer Pro ($67). Only tool under $3,000 with per-message SHA256 hashing and chain of custody reporting.
- Best for PST conversion/migration
- SysTools PST Viewer Pro ($299). Mature conversion engine with multiple output formats. Overkill for viewing but strong for migration.
- Best for PST recovery
- Kernel PST Viewer ($79). Purpose-built for recovering emails from corrupted PST files.
- Best comprehensive forensic suite
- FTK ($3,000+). The industry standard for full forensic analysis. Use it if you already have it. Do not buy it just for PST viewing.
- Best for IT administrators
- Sherlock PST Viewer Free. Opens PST and OST without Outlook, provides search and allows individual email export. Costs nothing.
Forensic Feature Comparison
For examiners and litigation support professionals, the forensic features are what matter. Here is a detailed breakdown:
| Forensic Feature | Sherlock Pro ($67) | SysTools ($299) | Kernel ($79) | FTK ($3,000+) |
|---|---|---|---|---|
| Read-only access | Yes | Yes | Yes | Yes |
| SHA256 per-message hash | Yes | No | No | Yes |
| Chain of custody report | Yes | No | No | Yes |
| Examination audit log | Yes | No | No | Yes |
| Batch export with hashes | Yes | Yes (no hashes) | Yes (no hashes) | Yes |
| Corrupted PST recovery | Yes | Limited | Yes | Yes |
| Expert witness support | Yes (same team) | No | No | No |
The gap is clear. Below FTK's $3,000+ price point, Sherlock PST Viewer Pro is the only tool that provides forensic-grade output. SysTools and Kernel are capable tools for their intended purposes (conversion and recovery), but they were not designed for courtroom use.
A Note on Pricing Honesty
We price Sherlock PST Viewer Pro at $67 USD because forensic examiners should not need to spend $299 on a conversion tool or $3,000 on a full forensic suite to analyze a PST file with integrity. One payment. No subscription. No annual renewal. The Pro license is permanent.
If your needs are limited to viewing PST files without forensic requirements, the Free edition does that with no strings attached. No trial period. No feature nag screens. No data collection.