Notes on hard Apple platform problems

I spent twelve years at Apple in Developer Technical Support, working as a deep escalation point for iOS, macOS and watchOS developers. The problems that reached me had usually already defeated the teams that filed them.

I retired in July 2026. This site is where I write down the answers that were hard to find, the behaviour that is documented incorrectly or not at all, and the things I found myself explaining over and over.

Everything here is free. If it saves you a week, that was the point.

Recent articles and notes

• ArticleA SensorKit fetch that returns nothing is usually asking for the wrong window22 September 2026A fetch cannot reach earlier than your app's authorization or later than 24 hours ago, and a range that breaks either rule returns no samples and no error.
• NoteThe default contactless app is woken by every reader22 September 2026Being the default NFC contactless app means any reader field wakes your app, not only the readers asking for the identifiers you declared. There is no filter, and there is only one default.

Browse everything by subject under Articles, or the shorter observations under Notes.