Repair Corrupted Excel Files (.XLS & .XLSX) Online or Offline on Windows

Restore unreadable, truncated, or damaged Microsoft Excel spreadsheets (.xls and .xlsx) using the same proprietary reconstruction engine in two ways: online in any browser or 100% locally on a Windows PC with Excel Repair Kit. Both options let you inspect your recovered worksheets for free before paying.

Online Excel Repair

The files will be automatically deleted from the server in 10 days.

Online Excel Repair Service ($10 per file): Upload your damaged .xls or .xlsx file from any phone, tablet, Mac, or PC browser with no software or local Microsoft Office installation needed. View your restored data on the free preview page and download a free DEMO recovery file before paying $10.

OR

Excel Repair Kit

download Download Download Excel Repair Kit for Windows PC

Excel Repair Kit for Windows (License from $25): Install the utility on your Windows computer to scan and reconstruct spreadsheets 100% locally so confidential data never leaves your PC. Inspect all recoverable sheets for free in the demo preview window and purchase a license starting from $25 to save unlimited files.

Updated:

Victor G. Bobrov Written by: Victor G. Bobrov

Online Browser Recovery ($10) vs. Offline Excel Repair Kit (From $25): Same Engine, Two Workflows

Unlike services that run a stripped-down script in the browser or restrict cloud uploads to 100 KB–1 MB, https://www.excel.repair/ and the desktop Excel Repair Kit share the exact same proprietary recovery engine. Your recovery depth for both legacy binary .xls files and modern .xlsx packages is identical across both tools.

Selection Criterion Online Service ($10) Excel Repair Kit ($25+)
Devices & OS Any browser (Mobile, Mac, PC) Windows 11, 10, 8, 7, Server
Internal Engine Proprietary BIFF8 & OOXML Same proprietary engine
Data Privacy Encrypted server upload 100% local offline on PC
Local Excel Needed No (runs in cloud) Preview: No / Save: Yes
Free Verification Web preview + DEMO file Built-in local preview
Demo Restriction DEMO masks restricted cells File saving disabled
Formats Supported .XLS and .XLSX .XLS and .XLSX
Best Pricing Fit $10 per single file From $25 (unlimited files)

How to choose the right option in 10 seconds:

Choose Online Recovery ($10/file) if you are on a smartphone, tablet, Mac, or a Windows PC without Microsoft Excel installed, or if you only need to fix 1 or 2 files immediately.

Choose Excel Repair Kit for Windows (from $25) if your workbooks contain sensitive financial or client data under strict NDA that cannot be uploaded to the internet, or if you have 3 or more damaged files to repair.

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30-Second File Pre-Check & 3 Mistakes That Destroy Recoverable Excel Data

Before starting an online upload or local scan, check your file properties in Windows Explorer or Finder. Filtering out lock files and avoiding destructive saves prevents permanent data loss.

Verify Your File Before Uploading or Scanning

  1. Skip 165-byte temporary lock files (~$filename.xlsx): While a workbook is open, Excel creates a hidden lock file starting with ~$ (such as ~$Sales2026.xlsx) measuring around 165 bytes. It contains only the user session name, not table data; always select the actual .xls or .xlsx workbook measured in kilobytes or megabytes.
  2. Confirm the file size is above 0 KB: If a crash or interrupted download left your spreadsheet at exactly 0 bytes, the file container holds no binary or XML streams to extract.
  3. Check if a ".xls" report is actually plain-text CSV or HTML: Banking and ERP portals often export raw HTML tables or comma-separated text with a forced .xls or .xlsx extension, triggering the "file format or file extension is not valid" warning. Open a copy in Notepad: if you see plain text or HTML tags on line 1, rename the file extension to .csv or .html.

3 Mistakes to Avoid

  • Never save a blank or partial window over the original filename: Clicking Save on an empty recovery screen permanently overwrites surviving worksheet streams inside your source file.
  • Copy the file out of OneDrive, SharePoint, Dropbox, or VPN folders first: Always move a copy of the damaged workbook to a local folder (such as C:\Temp) before scanning so background cloud sync or network drops do not overwrite sectors mid-read.
  • Never edit a corrupted workbook in Notepad or WordPad and save it: Resaving a binary .xls stream or compressed .xlsx archive in a text editor corrupts byte offsets and ZIP checksum headers beyond repair.

System requirements:

  • Windows Windows 11, 10, 7, and earlier versions; Windows Server 2025, 2022, 2019, and earlier versions.

Excel Corruption Diagnostic Matrix: Error Messages vs. Internal Data Survival

Microsoft Excel validates the entire file container before displaying a single cell. When a secondary structure—such as the style sheet, calculation chain, or tab index—breaks, Excel blocks the whole file even though your numbers, text, and formulas remain physically intact inside the worksheet streams.

Excel Error Symptom Damaged Component Standard Excel Action Engine Forecast
Unreadable content found xl/styles.xml or calcChain Halts on style mismatch High (data & formulas)
Invalid file format/extension ZIP footer or OLE2 header Rejects broken container High (byte-zero scan)
File is corrupt, cannot open xl/workbook.xml or .rels Loses sheet tab map High (rebuilds sheet tabs)
Missing text or garbled cells sharedStrings.xml or SST Breaks string pointers Moderate–High (remaps text)
Freeze or crash on launch Pivot cache or query loop Hangs memory on open High (drops broken cache)

How the closed engine bypasses container corruption:

  • For modern .XLSX workbooks (OOXML ZIP packages): Instead of relying on the damaged central directory at the end of the file, the engine scans directly for raw xl/worksheets/sheet1.xml...sheetN.xml streams, reconnects surviving text from xl/sharedStrings.xml, and writes a fresh, specification-compliant .xlsx package.
  • For legacy .XLS workbooks (Excel 97–2003 BIFF8 binary streams): The engine bypasses broken OLE2 Compound Document headers and extracts low-level cell records (RK, MULRK, NUMBER, LABELSST, and FORMULA) to rebuild every readable row and column.

What Our Closed Engine Restores vs. Simple Browser Scripts & Technical Limits

Free browser-only utilities typically rely on lightweight JavaScript parsers (such as standard SheetJS extractors) that scrape static cell values from .xlsx files while destroying all formulas, dates, and formatting. Our closed engine reconstructs both the data and the working logic of your spreadsheets.

Workbook Element Simple Browser Scripts Our Closed Engine User Impact
Legacy .XLS (97–2003) Unsupported Full BIFF8 recovery Saves old accounting files
Formulas & Functions Converted to static text Restored as live formulas Keeps financial models working
Dates & Currency Turned into serial numbers Preserves display masks No manual date reformatting
Styles & Merged Cells Stripped to plain grid Restores layout & widths Retains table hierarchy
Multi-Sheet Structure Fails without workbook.xml Rebuilds all surviving tabs Recovers complex workbooks
File Size Limits Capped at 100 KB–50 MB Server & local PC power Processes large tables

Detailed recovery scope and structural behavior:

  • Restored spreadsheet elements: Both the online service and Excel Repair Kit recover numeric values, shared text strings, editable formulas (SUM, VLOOKUP, XLOOKUP, IF, nested functions), cell formatting (fonts, colors, borders, number/date masks), merged cells, frozen panes, and column widths/row heights.
  • Macro-enabled (.XLSM) and template (.XLTX / .XLT) files: If you have a damaged .xlsm workbook, the engine extracts all readable worksheets, formulas, and formatting into a clean .xlsx file while stripping corrupted vbaProject.bin macro modules so the spreadsheet opens safely.

Hard Technical Boundaries

Passwords, Encryption, and Unrecoverable States

  • Sheet / Structure Protection vs. Open-File AES Encryption: Workbooks locked against editing (Protect Sheet or Protect Workbook) store cell data unencrypted and are recovered in full. However, files encrypted with a password required to open the file (Encrypt with Password using AES-128 or AES-256) are cryptographically locked and cannot be read without the password.
  • Corrupted VBA Macros and Pivot Caches: To prevent the repaired file from crashing Excel on launch, damaged VBA modules, ActiveX controls, and broken pivot table caches are excluded from the rebuilt output.

3-Stage Recovery & Pre-Purchase Verification Protocol

Both workflows operate in strict read-only mode on your damaged file and let you verify the exact recovery result before spending a dollar.

  1. Stage 1 — Start Non-Destructive Analysis: Upload your damaged .xls or .xlsx file in the online box at the top of this page (from any device) or open it inside Excel Repair Kit on your Windows PC for a 100% local offline scan.
  2. Stage 2 — Verify Your Data via Free Preview & DEMO File:
    • In the Free Preview Grid (Online & Offline): Click through every reconstructed worksheet tab on screen to inspect your restored rows, columns, text labels, and formulas at zero cost.

    • With the Downloadable DEMO File (Online Mode): Click Download Demo File on the online preview page and open it in Excel to confirm the rebuilt file structure opens without error prompts (while the browser preview shows your full recovered values, the downloaded demo file places "demo" placeholders on restricted cells until purchased).

      Online repair results with Preview and Download Demo buttons Recovered worksheet preview with DEMO watermark Online repair payment screen showing $10 USD

    • In the Offline Windows Demo: Review the complete recovered spreadsheet inside the Excel Repair Kit preview window for free; saving the recovered data to a new Excel file is disabled in the unregistered demo version.

      Excel Repair Kit demo with a source workbook selected Excel Repair Kit demo preview of recovered worksheets
  3. Stage 3 — Export the Clean Excel Workbook: Pay $10 online to immediately download the unmasked .xls or .xlsx workbook, or activate an Excel Repair Kit license (starting from $25) to export unlimited repaired files locally on Windows (using your local Microsoft Excel installation to write the output file). Recovered data is saved in .xlsx files in accordance with the ECMA-376 standard - Office Open XML file formats. The Excel Repair Kit allows direct export of data to a new Microsoft Excel workbook using COM/OLE.

4-Point Audit Checklist Before Paying

Take 60 seconds on the free preview screen to verify these four indicators before completing your purchase:

  1. Worksheet Tab Count: Check the bottom tab bar in the preview grid to ensure all critical sheets from your workbook were found and reconstructed.
  2. Bottom-Right Row Boundary: Scroll to the last row of your main table to confirm the file was not cut off mid-stream during a power outage or network drop.
  3. Shared Text String Integrity: Verify that text columns (names, SKUs, categories) display readable words rather than blank cells.
  4. Formula & Date Formatting: Confirm that date columns show formatted dates and formula cells contain live expressions rather than static error codes.

Errors:

The Excel Online Repair Service and Excel Repair Kit allow for fixing many errors in documents:

  • We found a problem with some content in FileName.xlsx (xls) .Do you want us to try to recover as much as we can? If you trust the source of this workbook, Click Yes.
  • Filename.xlsx cannot be accessed. The file may be read-only, or you may be trying to access a read-only location. Or, the server the document is stored on may not be responding.
  • Excel cannot complete this task with available resources.
  • This file is not in a recognizable format.
  • Excel found unreadable content in filename.xlsx.
  • File format not valid.
  • Microsoft Excel has encountered a problem and needs to close.
  • Unexpected error.
  • Excel unable to read file.
  • Cannot access read-only document.
  • The document Filename caused a serious error the last time it was opened.
  • Cannot open .xls file.
  • This file is not in a recognizable format.
  • The file is corrupt and cannot be opened.
  • Excel error cannot open file because the file format or file extension is not valid.
  • Excel cannot open the file .xlsx because the file format or file extension is not valid.
  • Error 1004.
  • Error 13.
  • Error 91.
  • File in Use error opening Excel 2007 Files.
  • .xls file format is not valid.

Resources

  • Microsoft Office - Microsoft Office, MS Office, or simply Office is a suite of office applications and, formerly, a family of client and server software and services developed by Microsoft.
  • Microsoft Excel - Microsoft Excel, or simply Excel, is a spreadsheet editor developed by Microsoft for Windows, macOS, Android, iOS and iPadOS. It features calculation or computation capabilities, graphing tools, pivot tables, and a macro programming language called Visual Basic for Applications (VBA).
  • LibreOffice - LibreOffice is a free, open-source suite of office applications developed by The Document Foundation (TDF). It was created in 2010 as a fork of the OpenOffice.org project, which was itself the successor to the discontinued StarOffice suite. The suite includes applications for word processing (Writer), spreadsheets (Calc), presentations (Impress), vector graphics (Draw), databases (Base), and formulas (Math). It supports the OpenDocument format and is compatible with other common formats, including those used by Microsoft Office.
  • OpenOffice - OpenOffice.org is an open-source suite of office applications. It was based on the proprietary StarOffice product developed by Star Division, which Sun Microsystems acquired in 1999. In July 2000, Sun released the software’s source code and presented it as a free alternative to Microsoft Office. OpenOffice.org 1.0 was released on May 1, 2002.
  • XLS files - Excel Binary File Format. Microsoft Excel File Format.
  • XLSX files - Office Open XML Spreadsheet Document, ECMA-376 1st Edition
  • Google Spreadsheets - Google Sheets is a spreadsheet program included as part of the free, web-based Google Docs Editors suite offered by Google. Google Sheets is available as a web application, as mobile apps for Android and iOS, and as a desktop application on ChromeOS. The service is compatible with Microsoft Excel file formats.
  • WPS Office Writer - WPS Office (an acronym for Writer, Presentation, and Spreadsheets; formerly known as Kingsoft Office) is a suite of office applications for Microsoft Windows, macOS, Linux, iOS, Android, Fire OS, and HarmonyOS, developed by the Chinese software company Kingsoft.
  • Office Open XML - Office Open XML (also informally known as OOXML) is an XML-based file format that uses ZIP compression and was developed by Microsoft to represent spreadsheets, charts, presentations, and word-processing documents. ECMA International standardized the initial version as ECMA-376, while ISO and IEC standardized later versions as ISO/IEC 29500.
  • ECMA-376 - Office Open XML file formats. ISO/IEC 29500.

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Publisher Accountability, Professional Credentials, and Protected File Processing

File Master creates and maintains this material. The page references the author's career profile, verified business records, legal policies, and customer-support options. These sources help readers and search engines confirm the specialist and company responsible for the Excel recovery guidance published here.

GOLD Partner

File Master LLC is a Microsoft Gold Certified Partner

This certification demonstrates our commitment to technical excellence, deep expertise in Microsoft technologies, and the ability to deliver high-quality solutions for Microsoft Access database recovery and file repair.

Verified Company Information

File Master's identity is documented through its official business profile and registered company information:

  • File Master corporate profile
  • Legal entity: File Master LLC
  • Technical help: File Master customer support

Privacy-Conscious Processing of Excel Files

  • For spreadsheets containing financial, commercial, engineering, or other sensitive data, use the desktop EXCEL Repair Kit. Recovery runs locally, keeping the workbook on your Windows computer.
  • Before trying any repair method, make a separate working copy of the damaged Excel file. Keep the original unchanged in case another recovery attempt is required.
  • When installing Windows software is impractical or impossible, the online Excel Repair Service provides a browser-based recovery option.
  • The license agreement, privacy policy, and support links remain easy to find, allowing visitors to review service rules and identify the organization responsible for the product.

Prices

Personal

License

$ 25

Buy now

Business

License

$ 39

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Site

License

$ 49

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Repair

Online

$ 10

Online
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PayPro Global (PayPro Global, Inc., 250 The East Mall street, Etobicoke, ON Canada, M9B 0A9) is the fastest growing eCommerce company that develops customized solutions to help software producers to easily and effectively sell software online. PayPro Global supports more than one hundred currencies, all major credit cards, and a wide variety of payment options. PayPro Global offers efficient customer support 24/7 and provides personal attention to customers having special requirements.

Renewal 1 Year

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License

$ 12

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Business

License

$ 19

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Site

License

$ 25

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Contacts

Pacific Business Centre, #101 - 1001 W. Broadway Suite 381.
Vancouver, BC V6H 4E4, CANADA
Email: email

Edge-Case Troubleshooting FAQ

01 FAQ #

Question:

Why is the downloaded DEMO file or final repaired workbook smaller than my original corrupted Excel file?

Answer:

A 20% to 70% reduction in file size after recovery is normal and does not mean table rows were lost. Corrupted workbooks frequently contain tens of thousands of duplicated unused style rules in xl/styles.xml, bloated pivot table caches (xl/pivotCache/), orphaned XML fragments, or accidentally formatted blank rows extending down to row 1,048,576. When our engine writes your salvaged cells, formulas, and active formatting into a fresh container, all dead binary padding and corrupted cache streams are removed.

02 FAQ #

Question:

Why do some formula cells display #REF!, #NAME?, or 0 when I first open the repaired workbook?

Answer:

To prevent Excel from freezing on launch, the recovery engine removes damaged calculation chains (xl/calcChain.xml) while preserving your actual formula expressions inside the cells. If formula cells display 0 or uncalculated values upon opening, press Ctrl + Alt + F9 in Microsoft Excel to force a complete recalculation across all worksheets. A #REF! value appears only if the specific worksheet tab or cell range referenced by that formula was physically destroyed in the source file.

03 FAQ #

Question:

What happens to cross-sheet formulas and links to external workbooks during recovery?

Answer:

Formulas that reference cells on other tabs within the same workbook (such as =SUM(Q1_Sales!B2:B200)) are preserved and relinked automatically as long as the target worksheet survived in the archive. Formulas pointing to a separate external Excel file on your drive are retained as formula strings; when you open the repaired workbook in Excel, click Enable Content or Update Links to reconnect them to the external source workbook.

04 FAQ #

Question:

Can I repair an .XLS or .XLSX file that was recovered from a formatted drive or deleted folder?

Answer:

Yes, provided the disk sectors were not overwritten before the file was undeleted. Raw disk recovery tools (such as Recuva, PhotoRec, or EaseUS Data Recovery) often reconstruct deleted files with damaged headers or mismatched trailing sectors. Upload the undeleted file to our online preview or scan it with Excel Repair Kit: if the internal OOXML worksheet streams or BIFF8 cell records survived on disk, they will appear in the free preview window; if the sectors were overwritten with zeroes or unrelated data, the preview will alert you before you spend any money.

Customer's reviews and ratings

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