iOS BGProcessingTask + Background Upload Not Executing Reliably on TestFlight (Works in Debug)
Description:
We are facing an issue with BGTaskScheduler and BGProcessingTask when trying to perform a background audio-upload flow on iOS. The behavior is inconsistent between Debug builds and TestFlight (Release) builds.
Summary of the Problem
Our application records long audio files (up to 1 hour) and triggers a background upload using:
BGTaskScheduler
BGProcessingTaskRequest
Background URLSession (background with identifier)
URLSession background upload task + AppDelegate.handleEventsForBackgroundURLSession
In Debug mode (Xcode → Run on device), everything works as expected:
BGProcessingTask executes
handleEventsForBackgroundURLSession fires
Background URLSession continues uploads reliably
Long audio files successfully upload even when the app is in background or terminated
However, in TestFlight / Release mode, the system does not reliably launch the BGProcessingTask or Background URLSession events.
Technical Details
We explicitly register BGTaskScheduler:
BGTaskScheduler.shared.register(
forTaskWithIdentifier: "example.background.process",
using: nil
) { task in
self.handleBackgroundProcessing(task: task as! BGProcessingTask)
}
We schedule it using:
let request = BGProcessingTaskRequest(identifier: "example.background.process")
request.requiresNetworkConnectivity = true
request.requiresExternalPower = false
try BGTaskScheduler.shared.submit(request)
We also use Background URLSession:
let config = URLSessionConfiguration.background(withIdentifier: sessionId)
config.sessionSendsLaunchEvents = true
config.isDiscretionary = false
AppDelegate.handleEventsForBackgroundURLSession is implemented correctly and works in Debug.
Issue Observed (TestFlight Only)
In TestFlight builds:
BGProcessingTask rarely triggers, or the system marks it as NO LONGER RUNNING.
Background upload tasks sometimes never start or complete.
No logs appear from our BGProcessingTask handler.
system logs show messages like:
NO LONGER RUNNING bgProcessing-example.background.process
Tasks running in group [com.apple.dasd.defaultNetwork] are 1!
This occurs most frequently for large audio uploads (30–60 minutes), while small files behave normally.
What We Have Verified
Proper Info.plist values:
Permitted background modes: processing, audio, fetch
BGTaskSchedulerPermittedIdentifiers contains our identifier
BGProcessingTask is being submitted successfully (no errors)
App has microphone permission + background audio works
Device plugged/unplugged doesn’t change outcome
Key Question for Apple
We need clarification on:
Why BGProcessingTask behave differently between Debug and TestFlight builds?
Are there additional restrictions or heuristics (related to file size, CPU usage, runtime, network load, or power constraints) that cause BGProcessingTask to be throttled or skipped in Release/TestFlight?
How can we guarantee a background upload continues reliably for large files (100MB–500MB) on TestFlight and App Store builds?
Is there an Apple-recommended pattern to combine BGProcessingTask + Background URLSession for long-running uploads?
Expected Result
Background uploads should continue reliably for long audio files (>30 minutes) when the app goes to background or is terminated, in the same way they currently function in Debug builds.
Topic:
App & System Services
SubTopic:
Processes & Concurrency
Tags:
iOS
Background Tasks
Foundation
CFNetwork