Description:
Trade show exports leads in latest strict ooxml format (ecma-376). LibreOffice (and also Google Drives) chokes on it and fails on the desktop. I have 25.8 LO on linux.

Oddly enought LibreViewer on my Android phone can view the xls just fine.

Actual Results:
LO sees as corrupt, tries to repair and then generates I/O error

Expected Results:
see the xls file


Reproducible: Always


User Profile Reset: No

Additional Info:
🔥 1. The new file uses “Strict OOXML” format (Excel 2013+ XML)

Most lead-scanner systems export using:

ECMA-376 Strict Open XML format

LibreOffice and Google Sheets struggle with “Strict” because:

LibreOffice still relies heavily on the Transitional OOXML standard

Google Sheets cannot reliably parse shared strings tables and extended properties

Older files (like your 2015 Excel export) used Excel 97–2003-compatible XML, which all platforms read easily.

🔥 2. The new file probably contains a very large sharedStrings.xml

Your 2025 sheet has 36 columns × ~1000 rows.
That can generate:

A huge shared string table

Long XML nodes

Repeated rich-text cell styling

Google Sheets is notorious for choking on XLSX files with large sharedStrings.xml maps.

The 2015 file is tiny, so it loads instantly.

🔥 3. The 2025 file contains “relationships” files that Sheets/LibreOffice ignore

Modern Excel exports include:

/xl/printerSettings/

/xl/drawings/vmlDrawing1.vml

/xl/styles.xml with extended fonts

/docProps/app.xml with custom properties

/xl/_rels/workbook.xml.rels

Google Sheets simply discards these and often errors.

Old file?
It had none of these.

🔥 4. The new file uses features not supported in LibreOffice or Google Sheets

Even if they aren’t visible to YOU, the exporting system may embed:

Custom cell formatting rules

“Hidden” metadata worksheets

Rich text XML within cells

Boolean flags for scanning devices

Date/Time stamps in OADate format

Unicode metadata from badges

These silently break non-Excel parsers.

Your 2015 file is simple text — no formatting, no metadata.

🔥 5. Google Sheets has a 10 MB internal processing limit for XLSX import

Even if the file is physically smaller than 10 MB, the XML expansion may exceed Google’s internal threshold.

A 1 MB XLSX can expand to >40 MB XML internally.

Your 2025 file has:

Many text fields

High repetition

XML-heavy lead system metadata

Your 2015 file is extremely lightweight.

🔥 6. EventLead / ExpoPass / Cvent / Aventri-style scanners export Excel using Microsoft's API

Their XLSX output expects Microsoft Excel, not compatibility tools.

LibreOffice reverse-engineers XLSX but does not fully support all XML rules (especially strict SAX-based parsing).