What is the TTS file format?
.tts files are associated with the ToolBook software suite. Files with the .tts extension store configuration data for the ToolBook Translation System. They can also contain information about databases referenced by ToolBook projects. .tts files are used by ToolBook to translate or localize projects saved in .tbk files, mapping application string IDs to their translated equivalents for each target language. In role and structure they are very similar to INI files, using bracketed section headers such as [English] or [German] with key=value pairs.
ToolBook is a Windows-based authoring tool for creating e-learning content, originally developed by Asymetrix and subsequently owned by Click2Learn, then SumTotal Systems (later part of Skillsoft). The Translation System extension allowed ToolBook authors to localize their courseware for multiple languages and reach as many users as possible. The product line was effectively discontinued around 2014-2016, so .tts settings files are rarely encountered outside legacy enterprise learning management system deployments.
Security & safety
RISK: LOWPlain text configuration files with no executable content. Safe to open in a text editor.
Format details
in a nutshell- MPEG Transport Stream video file (MPEG-TS) - Some tools export MPEG-2 Transport Stream video with .tts extension (variant of .ts/.m2ts); unrelated to the ToolBook format.
- TrueTime Session File (MATLAB/Simulink) - TrueTime real-time control simulator (Lund University) saves simulation sessions as .tts; niche academic tool.
- HP TeemTalk Terminal Session - HP TeemTalk Terminal Emulator (pre-installed on HP thin clients) saves terminal sessions as .tts files.
Programs that open TTS files
Windows2 apps
Notepad
Open-source Open in Notepad++ for syntax-highlighted INI-style editing of the localization strings. 
Notepad (built-in)
Built-in Right-click the .tts file → Open with → Notepad to view/edit the plain-text settings. Technical details
deep spec| Text encoding | ASCII/ANSI text (Windows-1252 or system codepage); no BOM |
| File structure | INI-style sections with `[LanguageName]` headers containing `key=value` translation pairs |
| String mapping | Maps ToolBook application string IDs (numeric or named keys) to localized text for each target language |
| LMS parameters | Also stores Learning Management System settings such as source database path and supported language list |
| Source pairing | Paired with ToolBook `.tbk` project files - the Translation System reads `.tts` at runtime to serve localized strings |
| Operating system | Windows-only; ToolBook is a Windows-exclusive application |
| Developer lineage | Asymetrix → Click2Learn → SumTotal Systems (Skillsoft); product EOL circa 2014-2016 |
| Typical file size | 1 KB - 200 KB depending on project string count |
| Line endings | Windows CRLF (`\r\n`) convention |
| Format identification | No binary signature; identified by `.tts` extension and INI-like plain-text content |
| Editor compatibility | Openable in any plain-text editor; the ToolBook runtime must be installed for the translation data to serve actual courseware |
| Syntax similarity | Structurally equivalent to `.ini` and `.cfg` files; dedicated to ToolBook localization string tables |
| Released | circa 1999-2003 (ToolBook II Instructor era; exact date unconfirmed) |
| Latest version | unknown; ToolBook product line last major update circa 2012-2014 |
TTS conversions
Community Q&A
asked by usersNo questions yet - be the first to ask about TTS files.
