iPhone 15 running slow

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Level 1

4 points

iPhone 15 running slow

Since 3/5/2025, my iPhone 15 Pro began running VERY slow. 2 hours on the phone and the battery was drained. After a restart, opening the Phone app would hang for 10-30 seconds and even after that the persona icons would be grey for almost 1 minutes and the status icons at the top would be missing for a few seconds(and go in and out). Also after restarting, opening the Message app would hang on a white screen for 1-2 minutes... and even after it opened person icons would be missing for a while, and functionality like voice to text would not work... I resolved this, keep reading if you are interested...

I read through other post and have been trying to fix it for 2-3 days... I did all of the recommendations and they did not solve the issue: Restart, verified storage was 80% or less full, verified I was on the latest IOS version(which I think an upgrade sent it over the edge into such poor performance...), reset network setting, turned off background app updates for all apps, checked the battery status was normal.... No luck!

A few weeks ago, I turned on Apple Intelligence.... tried a few things; then turned it back off as I noticed the phone seemed slower... It seem ever since then, my performance started degrading and continued to the current almost unusable state.

Here is what I did that fixed it:

1) Settings>Apple Intelligence & Siri TURN IT OFF

2) Settings>General>Transfer or Reset iPhone (I know it sounds scary, but it is not)

Choose RESET, Then select Reset All Settings This does not delete any data, messages, etc... just resets the settings(WIFI connections, Notification configurations, etc...).

Do NOT choose Erase All Content and Settings!!! This will reset your iPhone to factory defaults.

It will take a few minutes while the reset completes; but all of your apps, data, messages, contacts, etc... will still be there. And your phone will run much faster! You will have to re-setup some setting like WIFI connections, Notification configurations, Focus configurations, etc... but given its running like a brand new phone again - I thought the inconvenience well worth it. I hope this helps anyone with similar issues resolve them. Oh and after its reset -Leave Apple Intelligence OFF :)

iPhone 15 Pro, iOS 18

Posted on Mar 7, 2025 7:26 PM

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Answer 1

SravanKrA

Level 10

432,982 points

Mar 7, 2025 11:12 PM in response to mpstl

There may be several reasons due to which an iPhone may behave as described by you. Some of them could be...

Let's delve a bit deeper into some of them:

Storage: A full iPhone can definitely slow things down. Phones can experience performance issues when the storage is nearly full. Users can check their storage status by going to Settings > General > [Device] Storage. Deleting unnecessary apps, photos, or videos can free up space and improve performance. How to check the storage on your iPhone and iPad - Apple Support.
Battery Health: A degraded battery can impact performance. A deteriorating battery can impact the overall performance of an iPhone. Checking the battery health can be done by going to Settings > Battery > Battery Health. If the maximum capacity is significantly reduced, it might be time to replace the battery. Prolong and Maximise Battery Performance … - Apple Community
Incorrect Handling: Accidental drops or bumps can cause internal damage. looking at the Apple's guide on proper handling is a good step. Important handling information for iPhone - Apple Support (IN)
Environmental Issues: Extreme temperatures, dust, and water exposure can all be detrimental.
1. Keeping iPhone clean is an important step. Dust accumulation in the iPhone's ports and openings can affect functionality. Apple provides guidelines on how to clean iPhones safely, which usually involves using a soft, lint-free cloth to remove dust without causing damage. Cleaning your iPhone - Apple Support
2. Keep the iPhone within temperature limits. Phones are designed to operate within a specific temperature range. Exposure to extreme temperatures, especially in parked cars, can lead to overheating or other performance issues. If your iPhone or iPad gets too hot or too cold - Apple Support.
3. Addressing safety issues is also important: Important safety information for iPhone - Apple Support (IN)
Unauthorized Service: Servicing an iPhone through unauthorized channels can result in substandard repairs and void warranties. Users should always seek authorized Apple service centers for repairs and maintenance.
1. Repairs by unqualified technicians can introduce new problems. Find information about your warranty or AppleCare plan - Apple Support is helpful.
2. Modification / Alteration of an iPhone by a third-party vendor may cause issues beyond repair. --> Unauthorized modification of iOS - Apple Support (IN)
Jailbreak: Now, let's talk about jailbreaking. Jailbreaking removes Apple's restrictions, allowing for more customization and app installation outside the App Store. However, it can also lead to instability, security vulnerabilities, and issues receiving future iOS updates.

By considering all these possibilities, a comprehensive approach to troubleshooting the iPhone's behavior.

Understanding and addressing these factors can help you maintain the optimal performance and longevity of their iPhones. Following Apple's guidelines and seeking authorized support when needed are crucial for a positive user experience.

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Answer 2

mpstl Author

Level 1

4 points

Mar 8, 2025 9:00 AM in response to SravanKrA

Thank you for responding, but none of the additional items you listed apply to my situation.

Since Resetting All Settings, I can share it does reset them all - even more than I anticipated such as FaceId/Passcode, shortcuts... But, the performance improvement is still well worth the effort to re-configure everything.

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iPhone 15 running slow

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