What is the PRS file format?
A .prs file is a proprietary binary presentation created by Harvard Graphics for Windows, a leading presentation software package of the early 1990s. It stores slides containing text, charts, graphs, embedded bitmap images, and speaker notes in a format exclusive to Harvard Graphics for Windows versions 1 through 3.x.
Harvard Graphics was one of the dominant presentation tools of the DOS and early Windows era, before Microsoft PowerPoint became the market standard. The Windows edition used .prs for its slide decks, while Harvard Graphics version 4 introduced the .pr4 format. The product line went through several ownership changes; Harvard Graphics 98 was the final major release and the software has been effectively discontinued since.
The format is entirely obsolete. No actively maintained application reads .prs files reliably. Older versions of Corel Presentations claimed limited compatibility, but that support is also legacy. Users who need to recover content from .prs archives must typically locate Harvard Graphics for Windows 3.x running on period hardware or a virtualized Windows 3.1/95 environment.
The binary format is undocumented with no published magic bytes, making automated identification unreliable.
- The
.pr4extension superseded.prswithin the Harvard Graphics product line. - Embedded chart data and bitmap images may be partially identifiable through hex inspection.
- harvardgraphics.com has been inactive for years; no vendor support exists.
Security & safety
RISK: LOWLegacy binary presentation format; no known malware vectors. Content may include dated business data.
Format details
in a nutshell- Dart Player Presentation File - Some sources note .prs used by Dart Player for multimedia presentations.
- Sage ACT! Compressed Backup - ACT! CRM software reportedly uses .prs for some compressed data files.
Programs that open PRS files
Windows2 apps
Harvard Graphics for Windows (legacy)
Paid File → Open - requires an original Harvard Graphics for Windows 1-3 installation. Not commercially available; must source from vintage software archives.
Corel Presentations (legacy versions)
Paid File → Open → Harvard Graphics format (available in older Corel Presentations 8-10; import support may be absent in current versions). Technical details
deep spec| Format type | Proprietary binary presentation |
| Byte order | Little-endian (16/32-bit Windows era) |
| Encoding | Binary |
| Magic bytes | None published - proprietary format with no documented signature |
| Typical file size | 50 KB - 5 MB |
| Compression | None documented |
| Encryption | None documented |
| Version compatibility | Harvard Graphics for Windows v1, v2, v3.x only |
| Successor format | .pr4 (Harvard Graphics v4) |
| Color depth | Up to 24-bit (Windows GDI era) |
| Embedded content | Text slides, charts, graphs, bitmap images, speaker notes |
| Associated OS | Windows 3.1, 95, 98; DOS (early versions) |
| MIME type | application/octet-stream |
| Maintenance status | Obsolete - no actively maintained software reads this format |
| Released | 1991 (Harvard Graphics for Windows 1.0) |
| Latest version | Harvard Graphics for Windows 3.x (mid-1990s); Harvard Graphics 98 was last major release |
PRS conversions
Community Q&A
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