What is the SDW file format?
.sdw is a text document file format associated with the StarOffice software package. It uses an OLE2 Compound File Binary container - the same low-level structure as Microsoft .doc - with proprietary StarWriter streams inside for text, styles, formatting, and embedded objects. StarOffice was marketed as a more affordable alternative to Microsoft Office, but only managed to capture around 3% of the market. It was distributed as a paid product for some time, but became open source in 2000 when Sun Microsystems released OpenOffice.org based on the same codebase.
StarOffice 5.2 (2000) was the final release to use the binary .sdw format. StarOffice 6.x (2002) switched to the XML-based .sxw format, and later versions migrated to the open ODF standard.
StarOffice files
Besides .sdw files, StarOffice also supported the .sxw format (a format similar to DOCX from Microsoft Word). Some other file formats supported by StarOffice are:
.sdcand.sxcspreadsheet documents.sddand.sxomultimedia presentation formats.sdaand.sxddraw templates.sdbdatabase document.smfand.sxmformula templates
LibreOffice Writer retains read-only support for .sdw files. Apache OpenOffice 4.0 (2013) removed the ability to read legacy StarOffice binary formats, so LibreOffice is the recommended tool for accessing older .sdw documents today.
Security & safety
RISK: LOWSDW files are passive documents from a legacy format. OLE2 compound files theoretically can contain embedded macros or objects, but StarWriter macro support was minimal and the format is ancient enough that no active exploit targets exist.
Format details
in a nutshell- Sybase PowerDesigner diagram - Sybase (now SAP) PowerDesigner data modelling tool uses .sdw for some workspace/diagram files - entirely unrelated to StarOffice.
Programs that open SDW files
Windows3 apps
Apache OpenOffice
Open-source WARNING: Apache OpenOffice 4.0+ dropped SDW support. Only older versions (3.x) can open .sdw. Use LibreOffice instead. 
LibreOffice Writer
Open-source File > Open the .sdw - LibreOffice imports it via its legacy StarOffice filter. Immediately save as .docx or .odt since LibreOffice cannot save back to .sdw. 
StarOffice (legacy)
Paid StarOffice 5.x is the original application for SDW files. Discontinued by Oracle in 2011; not available for download. Historical reference only. 
macOS3 apps
NeoOffice
Freemium macOS-native fork of OpenOffice/LibreOffice - may open SDW files via legacy filter. Check current version compatibility.
LibreOffice Writer
Open-source File > Open the .sdw; same as Windows - convert to ODT or DOCX immediately. 
Linux2 apps
LibreOffice Writer
Open-source Best supported option on Linux - open .sdw and immediately export to ODT/DOCX. Technical details
deep spec| Container | OLE2 Compound File Binary Format (CFBF) - same low-level container as Microsoft .doc and .xls |
| Magic bytes | D0 CF 11 E0 A1 B1 1A E1 at offset 0 (OLE2 header); internal stream names distinguish SDW from other OLE2 files |
| Byte order | Little-endian |
| Encoding | Binary; proprietary StarWriter streams within OLE2 compound structure |
| MIME type | application/vnd.stardivision.writer |
| Encryption | Optional password protection (StarOffice built-in) |
| Format dialects | StarWriter 3.x, 4.x, and 5.x - each dialect is binary-incompatible with the others; most tools target the 5.x dialect |
| Typical file size | 10 KB - 5 MB (plain text to documents with embedded images) |
| Developer | StarDivision GmbH; acquired by Sun Microsystems (1999), then Oracle (2010) |
| Platform | Windows, Linux, Solaris, macOS (limited) |
| Superseded by | .sxw (StarOffice 6.x XML format, 2002), then .odt (ODF standard, 2005) |
| Current support | LibreOffice Writer (read-only import); Apache OpenOffice 4.0 removed SDW support entirely |
| Released | circa 1985 (StarWriter 1.0 for DOS); Windows version with .sdw: StarOffice 3.x, early 1990s |
| Latest version | StarOffice 5.2 (2000) - final release of the binary .sdw format; StarOffice 6+ switched to ODF |
| Specification | fileformats.archiveteam.org |
SDW conversions
Community Q&A
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