Summary: iOS 11.4.1 Mail app keeps crashing with a specific Exchange account. I didn't have this problem with iOS 10 on my iPhone 7 Plus. This all became an issue when I starting using iOS 11 and iPhone X.

I'm wondering is it something in my Exchange inbox that's causing the issue and if I can find out what it is, will deleting it help? Is this possibly due to a timeout issue? My exchange account has at least 300k emails in it. I'm in the process of cleaning that out.

I have done all the troubleshooting as far as deleting/adding the account again, restoring the backup of my iPhone, deleting read/delivery receipts from the inbox and it still crashes. I'm trying to decipher these logs/stack traces. I've attached part of a log below if that might help. Please let me know if this points out the issue and if I can fix it. Thanks in advance!

{"bug_type":"288","timestamp":"2018-09-05 09:09:24.12
-0400","os_version":"iPhone OS 11.4.1 (15G77)","incident_id":"48A9DAF4-59EB-44BC-AC64-BBF1195ACEBF"}


"build" : "iPhone OS 11.4.1 (15G77)",

"product" : "iPhone10,3",

"kernel" : "Darwin Kernel Version 17.7.0: Mon Jun 11 19:06:27 PDT 2018; root:xnu-4570.70.24~3/RELEASE_ARM64_T8015",

"tuning" : {


"incident" : "48A9DAF4-59EB-44BC-AC64-BBF1195ACEBF",

"crashReporterKey" : "89795b7b062045b5c64fe92ace4ef37c954cc667",

"date" : "2018-09-05 09:09:24.10 -0400",

"reason" : "scene-create watchdog transgression: com.apple.mobilemail exhausted real (wall clock) time allowance of 19.69 seconds\n\nProcessVisibility: Foreground\nProcessState: Running\nWatchdogEvent: scene-create\nWatchdogVisibility: Foreground\nWatchdogCPUStatistics: (\n \"Elapsed total CPU time (seconds): 24.660 (user 24.660, system 0.000), 21% CPU\",\n \"Elapsed application CPU time (seconds): 9.590, 8% CPU\"\n)",

"frontmostPids" : [




"exception" : "0x8badf00d",

"absoluteTime" : 315751083593,

Is this possibly due to a timeout issue?

The 0x8badf00d error code basically means an application is taking too long, so you're on the right track in terms of the most likely problem (i.e. it being a timeout issue).

I'm wondering is it something in my Exchange inbox that's causing the issue and if I can find out what it is, will deleting it help?

That certainly could explain it, although with 300K emails it may not be so easy to identify the culprit.

As a workaround/test you could try using another email client (such as MS Outlook) to see if that also encounters the same issue.

Also, if all your emails are in your inbox, you may want to try creating some Outlook Data Files (which basically appear as folders or separate mailboxes) to move bulk amounts of your email to to see if that helps you isolate the problem.


Apple's Developer Technical Q&A QA1693: Synchronous Networking On The Main Thread provides some additional info on the 0x8badf00d error code, although this is an archived document written for Developers.

I suspect the issue you're having is a little more involved (e.g. Mail may be performing other tasks that Outlook isn't, etc), and is therefore more sensitive to any potential problems with your MS Exchange data. I know that many organisations are even rolling out VMware's Boxer app because of issues accessing MS Exchange Server accounts on mobile devices.

  • I can run that same Exchange account perfectly fine in the iOS Microsoft Outlook app with no issue. I wonder is the coding for a timeout limit between iOS Mail App and iOS Microsoft Outlook App different. Is there a way I can change the timing or would that have to be an Apple Developer?
    – TechGuy1
    Sep 7 '18 at 5:37
  • @TechGuy1 It'd have to be done at Apple's end, assuming the problem is solely with the Mail app. It's probably related moreso with how Mail is allocating tasks as compared to how MS Outlook is doing it, but that's pure conjecture on my behalf. I've updated my answer to include a link to Technical Q&A QA1693 in case you (or others) are interested in a more technical discussion.
    – Monomeeth
    Sep 7 '18 at 7:07
  • I was so expecting 8badfood to be a sentinel pointer, but nope!
    – Joshua
    Oct 26 '20 at 15:34

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