The short version
- England missed 15,841 positive Covid results in a week because an old Excel format ran out of rows.
- No error message appeared. The data simply wasn't there.
- Good automation counts what goes in and what comes out, and raises the alarm when they differ.
Nobody pressed the wrong button. That's what makes it unsettling.
In early October 2020, England discovered that "almost 16,000 cases" of Covid had gone unreported, with 15,841 missed between 25 September and 2 October, iTnews reported.[1] Contact tracers lost days they couldn't get back.
A file format from 1987
The cause was mundane. Results were being moved through Excel's old .XLS format, "which first appeared in 1987" and "can only store 65,536 rows".[1] When files grew too big, new results fell off the bottom. No warning. No error. Just missing data.
It isn't rare
The European Spreadsheet Risks Interest Group keeps a running list of similar stories.[2] A US county found "a $331,074 Excel spreadsheet calculation error". A New Zealand festival "overstated net door donations by $157,413". Norway's sovereign wealth fund lost about "$92mn" after "an incorrect date was entered".[2]
The fix is a habit, not a person
None of these were caused by careless people. They were caused by fragile processes that relied on people never slipping.
The cheapest safeguard is the one England lacked: a check that counts what went in and what came out, and tells someone when they don't match. Connected systems do that automatically. Spreadsheets, passed from inbox to inbox, rarely do.
Sources
- iTnews: File format fail behind England's COVID case underreporting (6 Oct 2020)
- European Spreadsheet Risks Interest Group: Horror stories
Sources checked 7 November 2026. Product features and prices change often, so check the vendor's site before you buy.