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.SDC file extension

To open .SDC files on Windows, try opening it in Apache OpenOffice Calc (File → Open). If it opens as a spreadsheet, immediately save a copy to a modern format (e.g., ODS).

To open an .SDC file, determine whether it is a StarOffice/OpenOffice Calc spreadsheet or a Microsoft Secure Download Cabinet file. Calc spreadsheets can be opened with Apache OpenOffice (and often LibreOffice), while cabinet-type .SDC files are typically handled by Windows cabinet/extraction tools.

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Last updated: June 10, 2026 · Reviewed by Julian Stricker

What “reviewed” means on this page
  • Format fit: whether the “what is this file?” description matches common real-world use of the extension, including category, typical MIME types, and aliases.
  • Opening paths: whether Windows / macOS / Linux steps read plausibly for current OS dialogs and default apps; we remove fantasy menus and unsafe shortcuts.
  • Security framing: whether risk notes match the extension class (for example executables vs plain data) and whether affiliate wording does not contradict the security section.
  • Sources and further reading: whether external links point to vendors, standards bodies, or other primary references where possible; we avoid inventing details we cannot ground.
  • Limits: this is clarity and safety-messaging QA, not a guarantee that every statement is exhaustive or that every binary you download is harmless.

Full methodology in the Imprint — The Imprint also states where AI is used and what that does—and does not—replace.

Open on your device

Choose your operating system for a dedicated step-by-step opening guide.

How to open .SDC files

Use these platform-specific instructions to open .SDC files safely.

Windows

  1. Try opening it in Apache OpenOffice Calc (File → Open). If it opens as a spreadsheet, immediately save a copy to a modern format (e.g., ODS).
  2. If Calc reports it is not a valid spreadsheet, treat it as a cabinet/container: right-click → Open with and try a cabinet/extraction utility, or check the file’s properties to confirm it is not a spreadsheet.
  3. If you are unsure, use a file identification tool (or Properties/Details) to determine whether it looks like a document (spreadsheet) or a cabinet/archive, then open with the matching app.
Full Windows guide

Mac

  1. Use Apache OpenOffice (Calc) to open the .SDC file (File → Open). If successful, export/save to ODS for long-term compatibility.
  2. If it does not open in Calc, the file may be a Microsoft Secure Download Cabinet variant; macOS commonly lacks native handling, so transfer to a Windows PC or a Linux system with appropriate extraction tools.
Full Mac guide

Linux

  1. Open the file with Apache OpenOffice Calc from your desktop environment (or use your file manager’s “Open With”). If it opens, save to ODS.
  2. If Calc fails to open it, verify the file type (your file manager’s Properties or a terminal file-identification command). If it appears to be a cabinet/container, use an extraction tool suitable for cabinet-like files rather than a spreadsheet app.
Full Linux guide

iOS

  1. There is no widely documented native iOS support for .SDC; if Files cannot preview it, transfer it to a desktop (Windows/macOS/Linux) and open it with Apache OpenOffice Calc or an appropriate cabinet/extraction tool depending on the file type.
Full iOS guide

Android

  1. Android support is inconsistent for .SDC; if it won’t open in a document viewer, move the file to a desktop system and open it with Apache OpenOffice Calc (spreadsheet) or a cabinet/extraction tool (Secure Download Cabinet variant).
Full Android guide

Security notes

  • Treat unknown .SDC files cautiously because the extension is ambiguous: a file that looks like a spreadsheet may actually be a cabinet/container used for software distribution.
  • If the .SDC is a cabinet-like (Secure Download Cabinet) file, assume it may contain executables or installer components; only extract/run contents from trusted sources.
  • Even spreadsheet files can trigger vulnerabilities in parsers; prefer opening suspicious files in a dedicated office suite (e.g., Apache OpenOffice) and avoid enabling or running any embedded active content if prompted.

What can hide inside an archive

Compressed packages can contain executables or scripts you only see after extraction. Double extensions and nested archives are common tricks. Scan unexpected downloads before unpacking, and extract to an empty folder so you can review contents safely.

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Can't open this file?

These are the most common causes and fixes when .SDC files fail to open.

Common reasons

  • The .SDC file won’t open in a spreadsheet app
  • File opens but looks garbled or loses formatting
  • Linux desktop shows the wrong app for .SDC
  • “File is corrupted” or “invalid format” errors

Fix steps

  1. Try opening it with Apache OpenOffice Calc; if it fails, do not assume the file is a spreadsheet.
  2. Check the file type using your OS file properties or a file-identification tool; then use an extraction/cabinet tool if it’s a cabinet-like file.

OS-specific troubleshooting

What is a .SDC file?

.SDC is an ambiguous filename extension used by more than one format. In desktop office workflows it is best known as the StarOffice/StarCalc (later OpenOffice Calc) spreadsheet format, associated with the MIME type "application/vnd.stardivision.calc" and recognized in the freedesktop.org shared MIME database. Separately, .SDC can also refer to Microsoft Secure Download Cabinet files, which behave more like an archive/container used for distribution.

Background

In office/document contexts, .SDC is a legacy spreadsheet format used by older StarOffice StarCalc and Apache OpenOffice Calc. Modern office suites more commonly use ODS (OpenDocument Spreadsheet), but many tools can still open older .SDC files for migration or recovery.

The same .SDC extension is also reported to be used for Microsoft Secure Download Cabinet files. This is why some .SDC files “won’t open” in a spreadsheet program: they may be a cabinet-like container rather than a document.

On Linux and other freedesktop.org-based desktops, .sdc is recognized by the shared MIME-info database (typically mapping to the StarOffice Calc spreadsheet MIME type). However, extension-based detection is not perfect, so if the content doesn’t match, try identifying the file type (e.g., with your file manager’s properties or a file-identification tool) before choosing software.

Common MIME types: application/vnd.stardivision.calc

Further reading

Authoritative resources for more details on the .SDC format.

Common .SDC issues

The .SDC file won’t open in a spreadsheet app

Because .SDC is used by multiple formats, the file may not be a StarOffice/OpenOffice spreadsheet (it could be a Secure Download Cabinet file), or the spreadsheet may be corrupted.

  1. Try opening it with Apache OpenOffice Calc; if it fails, do not assume the file is a spreadsheet.
  2. Check the file type using your OS file properties or a file-identification tool; then use an extraction/cabinet tool if it’s a cabinet-like file.

File opens but looks garbled or loses formatting

Legacy StarOffice/OpenOffice formats can convert imperfectly in newer software, and some content/features may not map cleanly.

  1. Open in Apache OpenOffice Calc (closest known support) and then save/export to ODS.
  2. If you must use another suite, compare results after conversion and keep an original backup for reference.

Linux desktop shows the wrong app for .SDC

MIME detection is often based on filename globs; since .SDC is ambiguous, your system may associate it with the wrong handler.

  1. Use “Open With” to choose Apache OpenOffice Calc for spreadsheets (MIME commonly: application/vnd.stardivision.calc).
  2. If it is not a spreadsheet, change the association back and use a cabinet/extraction tool instead.

“File is corrupted” or “invalid format” errors

The file may be incomplete, damaged, or not actually an .SDC of the expected type.

  1. Re-download or re-copy the file to ensure it is complete, then try again.
  2. Confirm the file’s origin and intended application (spreadsheet vs cabinet) and open it with the correct software category.

FAQ

Is .SDC a spreadsheet or an archive?

Both exist. .SDC is commonly a legacy StarOffice/OpenOffice Calc spreadsheet, but it can also refer to Microsoft Secure Download Cabinet files (a container/archive-like format).

What program should I use to open an .SDC spreadsheet?

Apache OpenOffice Calc is a primary option documented for .SDC spreadsheets. After opening, save a copy to a modern format like ODS.

Why does my .SDC file open with the wrong application on Linux?

Desktop environments often rely on MIME associations and filename patterns. Because .SDC is ambiguous, you may need to use “Open With” and choose the correct application for your specific file.

Can I convert an .SDC file by renaming it to .ODS or .XLS?

No. Renaming only changes the extension. Open the file in a compatible application (such as Apache OpenOffice Calc for spreadsheets) and use Save As/Export to convert.

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