MakeFileWork

XLSX recovery · local processing

Excel cannot open the file? Diagnose and repair the XLSX

If Excel says “the file format or file extension is not valid”, “Excel cannot open the file” or it found unreadable content, drop the XLSX here. MakeFileWork first checks whether the file is really an XLSX, then reconstructs recoverable ZIP structure, validates the OOXML workbook and worksheet relationships, and returns only a result that passes conservative structural checks.

1Choose a file
✓ Private by design

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One file at a time · up to 40 MB · no account needed

✓ Processed in your browser whenever possible✓ Your file is not stored
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What MakeFileWork checks before repairing

MakeFileWork first identifies the real file format and the structure it can verify. A correct extension does not prove that the internal package is healthy. Diagnosis, conservative repair and verification are kept separate so a generated download is not presented as a complete recovery when critical parts are still missing.

What a verified result means

A verified result means the available checks for that file family passed after reconstruction or normalization. Evidence can include a valid ZIP container, essential OOXML relationships, a re-serialized PDF or recovered content that can be parsed again. It does not mean already-lost information can be recreated.

What may still need manual review

Visual layout, complex formulas, macros, embedded objects, signatures, fonts, images or optional parts can still need review in the original application. MakeFileWork reports partial or incomplete recovery when the evidence is not strong enough to claim a full repair.

Privacy and processing limits

Supported workflows run locally in the browser and enforce size and complexity limits to prevent uncontrolled resource use. Keep the original file until the repaired output opens and behaves correctly in the application you actually intend to use.

When an Excel workbook will not open

Modern XLSX files are ZIP packages containing workbook XML, worksheets, shared strings, styles and relationships. An interrupted save, damaged transfer or broken ZIP directory can make Excel reject the whole workbook even when useful worksheet data still survives.

What MakeFileWork verifies

After recovering the container, MakeFileWork checks the required OOXML package parts, confirms the Excel workbook main part, inspects worksheet references and validates that referenced worksheet parts still exist. If a worksheet is already proven missing, it can conservatively remove only that dead manifest reference rather than pretending the lost sheet was recovered.

See recovery evidence before download

For repaired XLSX files, MakeFileWork can show worksheet names and a bounded sample of recovered cell values locally before download. This helps distinguish a structurally repaired workbook with surviving data from an empty or incomplete recovery. Missing formulas, cells, charts or media are never fabricated.

Common Excel errors this workflow is designed for

This repair path is relevant when Excel reports “Excel found unreadable content”, “The file format or file extension is not valid”, “Excel cannot open the file” or a workbook corruption warning. You can also paste that rejection message into the assistant: the same repair-intent classifier routes the file into diagnosis and conservative recovery rather than a generic conversion.

Know what survived before trusting the result

A repaired download is not treated as proof by itself. MakeFileWork distinguishes verified or partial recovery from an incomplete Office package, and shows bounded recovery evidence before download when readable workbook content survives. Incomplete structural recovery is not presented as a successful repair.

Privacy

The current XLSX diagnosis, ZIP reconstruction, structural validation and preview run locally in your browser. Your spreadsheet is not uploaded for this repair flow.