What is the SMS file format?
.sms files are plain-text Package Definition Files (PDFs) used by Microsoft Systems Management Server (SMS), an enterprise software deployment platform introduced in the mid-1990s. Each file describes a software package that SMS distributes and installs silently across a managed fleet of Windows clients.
The format follows INI-style syntax: named sections such as [PDF], [Package Definition], and [Program] contain key=value pairs that specify the package name, publisher, version, source file paths, install and uninstall command lines, supported Windows platforms, and registry-based detection rules. There are no binary sections, compression, or encryption; any text editor opens an .sms file without issue.
SMS 1.x and 2.x relied on this format throughout the late 1990s and early 2000s. Microsoft renamed SMS to System Center Configuration Manager (SCCM) in 2007 and replaced the .sms Package Definition File with a MOF-based and later XML-based application model. SCCM was subsequently rebranded as Microsoft Endpoint Configuration Manager, now complemented by Microsoft Intune.
Finding an .sms file today means handling a legacy enterprise IT artifact, often from a software vendor's installation kit from the Windows NT or Windows 2000 era. The file reads as plain text in Notepad or any modern editor such as Visual Studio Code.
Security & safety
RISK: LOWThe .sms Package Definition File is a plain-text configuration - it cannot execute code by itself. However, the command lines it defines (install/uninstall programs) could reference malicious executables. On modern systems these files are inert; no SMS server exists to act on them. Treat as a text document.
Format details
in a nutshell- SMS Backup & Restore app backup file - Android SMS Backup & Restore (Carbonite/SynTech) exports text message backups as .sms XML files - completely unrelated to Microsoft SMS; far more common today.
- Sega Master System ROM image - Some emulation communities use .sms for Sega Master System game ROM files, though .sms is not the standard extension (usually .sms is accepted alongside .gg and .rom).
Programs that open SMS files
Windows3 apps
Visual Studio Code
Open-source Open as text file; syntax highlighting via INI extension helps readability. Free. 
Microsoft System Center Configuration Manager (SCCM)
Paid Legacy import: SCCM 2007+ can import older SMS package definitions via console wizard, but .sms format support is deprecated. 
macOS1 app
Text editor (any)
Open-source Open with VS Code, TextEdit, or any plain-text editor - the file is plain ASCII. Technical details
deep spec| Encoding | Plain text, ASCII (Windows-1252 on legacy Windows systems) |
| Format structure | INI-style named sections and key=value pairs |
| Common section headers | [PDF], [Package Definition], [Program], [Supported Platforms] |
| Package content defined | Name, publisher, version, source paths, install/uninstall command lines, supported Windows versions, registry detection rules |
| Binary signature | None - plain text file, no magic bytes; inspect with any text editor |
| Typical file size | 1 KB - 50 KB |
| Introduced with | Microsoft Systems Management Server 1.0 (1994-1995) |
| Last relevant version | SMS 2.x / early SCCM era (before ConfigMgr 2007) |
| Successor format | MOF-based definitions (SMS 2003), then XML application model (SCCM 2007+) |
| Current product | Microsoft Endpoint Configuration Manager / Microsoft Intune |
| Associated OS | Windows Server and Windows clients in SMS-managed enterprise environments |
| MIME type | text/plain |
| Released | Microsoft Systems Management Server 1.x (mid-1990s) |
| Latest version | Format last relevant in SMS 2.x / early SCCM (before ConfigMgr 2007) |
| Specification | oa.mo.gov |
SMS conversions
Community Q&A
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