WebKitBlobResource error 1 when using FileReader to read large file chunks in iOS Safari

Reading a large file in chunks via FileReader.readAsArrayBuffer() in iOS Safari works for the first ~60 seconds, then fails with: nginx Copy code WebKitBlobResource error 1 This prevents continued processing of the file. It works fine in Chrome, Firefox, and Android.

This is a known WebKit bug on iOS/Safari: access to file inputs via Blob/FileReader is revoked after exactly ~60 seconds, causing WebKitBlobResource error 1 on further reads Stack Overflow+1Stack Overflow+1Stack Overflow+2WebKit Bugzilla+2Apple Developer+2Apple Developer. On desktop Safari or other browsers, this timeout does not occur. Workaround: • Process files in one or a few large chunks, rather than many small ones over time. • Use readAsArrayBuffer() immediately after file selection without delay. • Avoid long-running setInterval–based chunk processing before reading input again. • If processing takes >60 seconds, consider uploading the file immediately or using Web Workers started within that timeframe.