XLSX won't open: workbooks that were not made by Excel
Excel opens the workbook, but another program says "sheet not found" or shows nothing. More often than not the file is not damaged — it simply was not produced by Excel. The format allows several ways of writing the same thing, and not every reader knows all of them.
Free for personal use. Workbooks with this kind of markup open just like ones saved by Excel. Windows version — 3.5 MB, no installation: details. Organizations: license.
How an .xlsx file is built
An .xlsx file is a ZIP archive. Inside you will find xl/workbook.xml with the list of sheets, xl/_rels/workbook.xml.rels that says which sheet lives in which file, the sheets themselves in xl/worksheets/, a shared string table and styles. Rename a copy of the file to .zip and you can see all of it with your own eyes.
What makes a workbook "not from Excel"
Reporting tools, ERP and accounting systems, and programs that generate workbooks through the OpenXML SDK write correct but unusual XML:
- A prefix on every element:
<x:sheet>,<x:row>,<x:c>instead of<sheet>,<row>,<c>. For XML these are identical — the prefix only points to a namespace. But a reader that looks tags up by their literal name finds no sheets at all. - Absolute paths in relationships:
/xl/worksheets/sheet1.xmlinstead ofworksheets/sheet1.xml. - A BOM (byte order mark) at the start of every XML file.
- Text stored directly in the cell (
t="str"or inline strings) instead of the shared string table, and dates written as text.
The app understands all of this: the prefix declared for the spreadsheet namespace is stripped before parsing, and paths and BOMs are handled.
If the workbook still won't open
| Symptom | What is going on |
|---|---|
| The file does not unzip as a ZIP | it is not an .xlsx workbook: a CSV or HTML file renamed to .xlsx, a password-protected workbook (those use a different container), or a corrupted file |
There is no xl/workbook.xml in the archive | it is some other ZIP-based document — for example a Word or ODS file with the wrong extension |
| A sheet is larger than 384 MB unpacked | too much to parse in a browser: export the data to CSV from the source system |
FAQ
Why does Excel open such a workbook while other programs don't?
Excel reads XML by the rules, namespaces included. Many other programs look tags up by their literal name for speed and trip over the prefix.
Can I re-save the workbook to make it "normal"?
Yes — open it in Excel and save it again, and Excel rewrites the markup its own way. You don't need to do that here, though: the workbook opens as it is.
Dates in such a workbook came out as text — what now?
Nothing: if almost every value in a column is a date written as text, the column is recognised as a date. More in Dates stored as text.
Free for personal use. Your file is not uploaded to a server. Windows version — 3.5 MB, no installation: details. Organizations: license.