iPhone 17 app pages disappear and reappear

You may check for it under the App Library. Next to the last page of the Home Screen. If it is in the App Library Touch, Hold and Drag the icon to Home Screen. That's it.

Probably some pages may be hidden

Here's how to hide/unhide a page:

1. Touch and hold an empty area on your Home Screen.
2. Tap the dots near the bottom of your screen.
3. Tap and Tick the circle under the page that you want to unhide.
4. Tap Done.

Please see the pic below which is self-explanatory

You may --> Organize the Home Screen and App Library on your iPhone

1. Is this your corporate/organisation/enterprise/School Management iPhone? Then please contact the system administrator of your corporate//organisation/enterprise/School Management
2. If it is your device, in that case, do you have any profile installed by your corporate/organisation/enterprise/School Management?
   1. Erase the profile added by you If you have installed a profile on your own --> Install or remove configuration profiles on iPhone - Apple ...
   2. Or please contact the system administrator of the organisation who provided the profile to you

A corporate profile installed on your iPhone could potentially be contributing to the inaccessibility of certain features. 

Here's why:

• Restrictions: Corporate profiles can have restrictions placed on apps and functionalities. These restrictions might be limiting some activity, causing it to be unresponsive or quit.
• Managed Apps: IT departments might deploy specific navigation apps through the profile, potentially blocking certain functions or features.
• Security Settings: Corporate profiles often have stricter security settings that could affect app or function behavior. This might be causing unexpected behavior of an App or functions.

Here's what you can do:

• Check with IT: The best course of action is to contact your IT department. They can explain the restrictions set by the corporate profile and see what is affected. They might be able to adjust settings or suggest alternative apps or features approved for corporate use.
• Look for App Conflicts: See if your IT department uses a different app through the corporate profile. Conflicting apps might cause crashes.

Additional points to consider:

• Even if the profile isn't directly affecting the function, it's still a good idea to check with IT. They might be aware of similar issues and have workarounds.
• While troubleshooting, make sure you prioritize safety. Don't fiddle with your phone. 

By working with IT and considering these possibilities, you can hopefully identify if the corporate profile is the culprit and find a solution that allows you to use the iPhone to your liking.

If you feel an unauthorized person/app is remotely using, controlling or monitoring your device, then that is possible only if you have done one or more of the following Don'ts...

1. Don't hand over an iPhone to kids or to a stranger without Enabling Guided Access
2. Don't share Apple IDs
3. Don't Jailbreak
4. Don't share sensitive information pertaining to your device
5. Don't give in to Phishing
6. Don't plug in your device in Airports and Public places through third-party cables and trust the device. Beware of Juice Jacking. (Especially in India)
7. Don't leave your iPhone unlocked and unattended in public places like offices, schools, malls, etc.

If one of the above is true then quickly change the Apple ID Password and Return iPhone settings to their defaults.

1. Immediately change your Apple ID password
   1. Go to Settings → [your name] → Sign-In & Security → Change Password.
   2. This signs out anyone using your account.
2. Enable Two-Factor Authentication (if not already): Same menu → Two-Factor Authentication → Turn On.
3. Check for any unknown devices linked to your account:
   1. Settings → [your name] → Devices.:
   2. If you see anything you don’t recognize, tap it → Remove from Account.
4. Check for unknown profiles or device management:
   1. Settings → General → VPN & Device Management.
   2. If you see a profile you didn’t install, tap it → Remove Profile.
5. Check Accessibility & Screen Sharing settings
   1. Settings → Accessibility → Switch Control, Voice Control, or Remote Control — turn off anything you didn’t set up.
   2. Settings → General → AirPlay & Handoff → make sure AirPlay is set to Ask or Never Automatically.
6. Sign out of iCloud everywhere and reset
   1. Go to Settings → [your name] → Sign Out (you’ll need your password).
   2. Then back up your photos to iCloud or your computer.
   3. Go to Settings → General → Transfer or Reset iPhone → Erase All Content and Settings.:
   4. Set it up as a New iPhone (not from a backup), so nothing suspicious is restored.
7. Update iOS: Always keep the latest iOS version for security fixes.

If a person has ever had your passcode, they could’ve installed something quietly — so the full erase and setting up as new is the safest option. How to factory reset your iPhone, iPad, or iPod touch