What is the MPJ file format?
.mpj is the project file format used by Minitab statistical software from version 12 (1998) through version 18. It stores a complete analysis session in a single file using the OLE2/CFBF (Microsoft Compound File Binary Format) container - the same binary structure that underlies legacy .doc and .xls files.
A single .mpj file captures the full working state: one or more worksheets with tabular data, the Session window output showing statistical results, all graphs and charts created during the session, the command history, and any ReportPad content. This allows analysts to share or archive an entire Minitab project in one portable file.
Minitab 16 through 18 used .mpj as the default project format. Minitab 19 (2019) introduced .mpx as the new default - a ZIP archive containing JSON sub-files that is easier to inspect and more portable. Minitab 19 through 21 retain full read support for legacy .mpj files, though they save new work as .mpx by default.
The OLE2 container uses no compression or encryption. File sizes range from 50 KB for simple worksheets up to 100 MB for projects with many large datasets and embedded graphs.
Users on macOS with Minitab 20+ may encounter compatibility issues opening .mpj files created in Minitab 14 or earlier.
Security & safety
RISK: LOWMPJ is a data file with no executable content. The OLE2 container format has historically been exploited by malicious Office macro documents, but an MPJ file does not contain VBA/macros - just Minitab data structures. Standard caution when opening files from unknown sources applies.
Format details
in a nutshell- MediaPipe JSON project file - Some versions of MediaPipe or similar ML tools use .mpj for project configuration - unrelated to statistics.
Programs that open MPJ files
Windows1 app
Minitab
Paid File > Open > Project, select the .mpj - works in Minitab 16 through 21; re-save as .mpx for future use. 
macOS1 app
Technical details
deep spec| Container | OLE2 / CFBF (Microsoft Compound File Binary Format) |
| Magic bytes | D0 CF 11 E0 A1 B1 1A E1 at offset 0 - standard OLE2 signature, identical to legacy .doc and .xls files |
| Byte order | Little-endian throughout (OLE2 standard) |
| Internal streams | Worksheets (tabular data), Session window output (text), embedded graphs, command history, ReportPad content, linked document references |
| Typical file size | 50 KB - 100 MB depending on worksheet count, dataset size, and number of embedded graphs |
| Software version range | Introduced Minitab 12 (1998); supported through Minitab 18; read-only support retained in Minitab 19-21 |
| Superseded by | .mpx (Minitab 19, 2019) - ZIP archive of JSON and media files; default format in Minitab 20+ |
| Integrity check | None - OLE2 has no built-in checksum |
| Platform | Windows (all versions); macOS (Minitab 20+, with limited compatibility for .mpj files from Minitab 14 or earlier) |
| Inspect note | The .mpx successor can be renamed to .zip to browse its JSON content; .mpj (OLE2) requires a compound file viewer |
| Released | 1998 (Minitab version 12; MTW worksheets adopted OLE2 simultaneously) |
| Latest version | Legacy; superseded by MPX (Minitab 19, 2019) |
| Specification | support.minitab.com |
MPJ conversions
Community Q&A
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