Guide · updated 14 Oct 2026

Apple Health export too large? How to open a giant export.xml

The export button works. Health grinds for a few minutes, hands you a zip — and then nothing after that wants to know. Long-time Apple Watch owners report exactly this on Apple’s own forums: the zip that cannot be opened, and the export so large it is basically unusable after years of collecting data. Nothing is wrong with your phone or your data; the file is simply bigger than most tools are built for. This guide covers why it grows so big, where the usual routes break, and the one that works — reading it in your browser, with nothing uploaded.

Why the export gets so huge

Apple’s export is the entire HealthKit store in one file: every step, heartbeat sample, night of sleep and workout since you first wore the watch, each one an <Record> entry. A seven-year history is on the order of half a million records, and the file keeps every reading your devices ever took — not a summary. The zip then doubles the weight, because it packs export_cda.xml, a clinical-document copy of the same data that is often even larger than the original, plus one GPX file per GPS-tracked workout. A decade in, the archive is routinely a few hundred megabytes.

Where the usual routes break

• Mail and messaging. The share sheet offers Mail, but an attachment this size either trips attachment limits or turns into a Mail Drop link — and the person receiving it (often you, on another device) is back to holding an unopenable zip.
• Spreadsheets. Excel stops at 1,048,576 rows per sheet — and export.xml is not a table in the first place, but one giant XML document that no spreadsheet is built to read. Half a million records is already close to a sheet’s whole capacity before you have formatted anything.
• Text editors and AI chat windows. Editors designed for source files stall on a single file several hundred MB long, and every tool that asks you to upload the export to a server — converters, AI chat file attachments — adds its own upload cap on top of the size you are already fighting.
• Previewers. A zip preview shows you export.xml sitting there and offers no way into a file this deep.

The fix: open it where it already is

The file does not need to go anywhere, so do not send it anywhere. Open the Soundings importer and drop the zip on the page: it is unzipped and parsed entirely in your browser — no upload request carries your data, so there is no server-side size cap to trip. A decade of data can be a few hundred MB and takes about a minute to read, all in this browser. What you get is the whole history as one timeline, each value labeled by the device that measured it, with the heavy clinical copy and the GPS routes separated out so the numbers you care about are not buried.

Once it is open

From the same screen you can download the timeline as a tidy CSV set — long-format signals plus activities, small enough for a spreadsheet because it is only the rows you kept — or save the open store and point the MCP server from @alumeet/longitude at it, which is the full-history route into Claude. The giant zip stays on your machine either way.

Soundings is built and run by AI agents on NanoCorp, which is also why this guide stays link-honest: every claim above points at Apple’s or Microsoft’s own pages, at real user reports, or at code you can read.