iPhone 17 Pro Max overheating and draining battery when using Outlook app - iOS 26.2

Hey there,

 A few users have reported severe Outlook battery drain + device overheating patterns very similar to what you’re describing, especially when Outlook gets stuck in a background sync or authentication loop. The fact that heat stops immediately when the app is closed is a key signal that this is an app-level issue, not hardware.

Below is a structured way to diagnose and mitigate it, based on what actually causes this behavior.

Disable background activity inside Outlook

Open Outlook → Settings → Accounts

For each account:

• Turn off:

• Background App Refresh

• Calendar sync (temporarily)

• Contacts sync

• Set Mail Sync to Manual

Then force-close Outlook and restart the phone.

If battery drain stops → you’ve confirmed a sync loop.

Remove Face ID from Outlook

This one is critical given your login issues.

Outlook → Settings → Security →Disable Face ID →Use passcode only for now.

If Face ID is looping authentication requests, this alone can stop the CPU spike.

Temporary workarounds (if Outlook remains unusable)

Until Microsoft fixes it:

• Use Apple Mail + Calendar (they’re far lighter on battery)

• Or access Outlook via Safari

• Keep Outlook off Background App Refresh

• Avoid Face ID for Outlook

I recommend you to check out this support article →If your iPhone or iPad gets too hot or too cold - Apple Support

Hope these help!

This is happening to me too. Exact same symptoms. It’s not related to iOS version. It started happening to me immediately after updating the Outlook app. Please send a support request via the app. They’re telling me they don’t have any other reports of the issue, so don’t seem to be taking it seriously. It’s clearly a very bad bug in the app.

📱Facing iPhone heating issues? Here's what worked for me on my iPhone:

1️⃣ Backup on iCloud/iTunes

2️⃣ Log out of Apple ID

3️⃣ Erase (Keep eSIM Data)

❌ DO NOT restore from backups! Set up as a new iPhone. Wait 2-3 days - no issue! That Indicates...

✅ No hardware/ iOS issue

Now...

📦 Restore data gradually

🔍 Find app/settings causing heat

My experience says this is purely caused by some third-party app that you may have installed.

I am not aware of the ambient temperature in which you are using the iPhone. However --> Keeping iPhone, iPad, and iPod touch within acceptable ...

Store the device where the temperature is between -20º and 45º C (-4º to 113º F). Don’t leave the device in your car, because temperatures in parked cars can exceed this range.

Use iOS devices where the ambient temperature is between 0º and 35º C (32º to 95º F). Low- or high-temperature conditions might cause the device to change its behavior to regulate its temperature. Using an iOS device in very cold conditions outside of its operating range might temporarily shorten battery life and could cause the device to turn off. Battery life will return to normal when you bring the device back to higher ambient temperatures. Using an iOS device in very hot conditions can permanently shorten battery life.

Sounds like a plan. Keep checking for updates too. Don’t hesitate to delete the app before you update. WhatsApp was having a similar issue a couple months ago. The bug fix would only work, if you deleted the app first. Wouldn’t surprise me if MS works the same way.I hope you have a great weekend.

Have you tried deleting the app and downloading a fresh copy from the Apple App Store? Outlook was most recently updated by Microsoft 6 days ago and in total 7 times in the last month. Sounds like an app with a lot of problems when every update says bug fixes and improvements. Have you talked to Microsoft’s support team? If so, what did they say?

This has been fixed in the latest Outlook iOS app update.