What is the MLT file format?
A .mlt file is a Forecast Pro Multivariate Text File - a plain-text, semicolon-delimited data file used to import historical time-series data for causal (driver-based) forecasting into Forecast Pro, the statistical forecasting software published by Business Forecast Systems, Inc.
The format dates to the 1990s and has remained a lightweight import mechanism rather than a project file: it carries raw data, not model settings or results. A typical .mlt file opens with one or more record headings followed by a semicolon, then per-variable header information and rows of decimal historical values. Two consecutive semicolons (;;) mark the end of the file. Because the format is plain text with no binary signature or magic bytes, file-type detection relies entirely on this structural convention.
.mlt files are commonly hand-authored or generated by exporting from a spreadsheet such as Microsoft Excel, then imported into Forecast Pro for multivariate analysis. Any text editor or CSV-capable tool can open and edit the data - the file carries no encryption or compression, and its MIME type is text/plain, the same as an ordinary .txt file.
Be aware that the .mlt extension is also used by the MLT Multimedia Framework project file (produced by the Shotcut video editor), which is a completely different, XML-based format. Always inspect the file's content to confirm which type you have.
Security & safety
RISK: LOWA Forecast Pro .mlt is plain text - no macros or executable code - so it is safe to open and inspect in any editor. The only real caution is overloaded identity: confirm whether your .mlt is forecasting data or a video project before acting, and beware disguised double extensions (data.mlt.exe).
Format details
in a nutshell- MLT / Shotcut video project (XML) - XML multimedia editing project used by Shotcut, Kdenlive and the MLT framework; starts with <?xml ... <mlt>.
- Magic Lantern Toolkit / misc app data - Various niche applications have used .mlt for internal data or template files.
Programs that open MLT files
Windows3 apps
Forecast Pro
Paid Import the .mlt as a multivariate data file, then build the forecast (this is the program that defines the format). 
Microsoft Excel
Paid Open/inspect the tabular data; useful for preparing or checking the numbers (save back as the required text layout). 
NotePad++ text editor
Open-source Open the .mlt to read or fix the semicolon-delimited layout before importing into Forecast Pro. 
macOS1 app
Any text editor (TextEdit/BBEdit)
Freemium View/edit the plain-text data (Forecast Pro itself is Windows-only). Technical details
deep spec| Format category | Plain-text, semicolon-delimited time-series import file |
| Character encoding | ASCII / ANSI (Windows-1252 compatible) |
| Delimiter | Semicolon (`;`) |
| End-of-file marker | Double semicolon (`;;`) signals the end of all data records |
| File signature | No fixed binary signature; file type identified by structural content (record headings + semicolon conventions) |
| MIME type | `text/plain` |
| Data content | Historical multivariate time-series values stored as decimal numbers |
| File structure | Record headings block → per-variable header lines → decimal data rows → `;;` terminator |
| Typical file size | 1 KB - 2 MB |
| Associated software | Forecast Pro (Business Forecast Systems, Inc.) |
| Operating system | Windows |
| Use case | Causal / driver-variable forecasting model input; supplies independent (explanatory) series to Forecast Pro |
| Editability | Intended to be hand-authored or prepared in a spreadsheet or text editor outside Forecast Pro, then imported |
| Variable support | Accommodates multiple independent (driver) variables per file, enabling multivariate model input |
| Import role | Data-only artifact - carries no forecast model parameters, settings, or output results |
| Extension collision | Shares the `.mlt` extension with the unrelated MLT Multimedia Framework XML project format used by Shotcut |
| Released | 1990s (Forecast Pro for Windows) |
| Latest version | Defined by current Forecast Pro release (TRAC/Unlimited/V12-era) |
| Specification | www.forecastpro.com |
MLT conversions
Community Q&A
asked by usersNo questions yet - be the first to ask about MLT files.
