iCloud sync breaks in predictable places: Apple's service status, the Apple Account on the device, the app's iCloud switch, Photos status, storage, or Windows setup. Work through the checks in order, starting with the ones that change nothing, then move to the exact settings Apple uses now.
Check Apple System Status first
Start here before changing a setting. Open Apple System Status and check the iCloud service that is failing: iCloud Drive, iCloud Photos, iCloud Contacts, Calendars, Reminders, or Bookmarks & Tabs.
If that service shows an outage or maintenance, wait for Apple to clear it. Device changes do not repair a server-side iCloud problem.
If the service is normal, continue with sign-in and sync settings on the device that is behind.
Use the same Apple Account everywhere
Use this when one iPhone, iPad, Mac, PC, Apple Watch, Apple TV, Apple Vision Pro, or iCloud.com is missing data that appears somewhere else.
On iPhone, iPad, or Apple Vision Pro, open Settings and tap your name; on Mac, open System Settings and click your name at the top of the sidebar. Confirm the same Apple Account is signed in.
Apple TV 4K uses a different route: open Settings > Users and Accounts, select your account, and if you are not signed in yet, choose iCloud > Sign In. An Apple Watch paired with your iPhone inherits that iPhone's iCloud settings, so check the iPhone instead; a watch set up by a family member has its own Settings app for turning iCloud on or off.
If the wrong account is signed in, sign in with the Apple Account that holds the missing iCloud data.
On Windows, open iCloud for Windows and sign in with that same Apple Account. On iCloud.com, sign in with that same Apple Account before comparing the data.
After changing your Apple Account password, update the sign-in information for every iCloud service on that device, then check sync again.
Update software and meet iCloud requirements
For missing iCloud features, the main software cause is a device that does not meet Apple's current iCloud requirements.
On iPhone or iPad, open Settings > General > Software Update and install the available update.
On Mac, open Apple menu > System Settings > General > Software Update. On Apple Vision Pro, open Settings > General > Software Update.
Apple's recommended versions are iOS 26 for iPhone, iPadOS 26 for iPad, macOS Tahoe 26 for Mac, watchOS 26 for Apple Watch, tvOS 26 for Apple TV, visionOS 26 for Apple Vision Pro, and Windows 11 with iCloud for Windows 15 on PC. For Outlook sync on Windows, use Outlook 2021 or later.
Turn on iCloud for the app that is not syncing
iCloud works by app, so turn on the exact app or service that is behind.
- 1.On iPhone, iPad, or Apple Vision Pro, open Settings > [your name] > iCloud > See All next to Saved to iCloud, tap the app, and turn syncing on.
- 2.On Mac, open Apple menu > System Settings > [your name] > iCloud, then under Saved to iCloud, click the app; if it is hidden, click See All.
- 3.On macOS Sonoma or earlier, use Apps Using iCloud > Show More Apps, then turn on the app.
- 4.On Windows, open iCloud for Windows, click the arrow button next to each app, turn syncing on, and choose Done.
- 5.For iCloud Drive, turn on Drive or iCloud Drive on the device, then sign in to iCloud.com with your Apple Account and click Drive or iCloud Drive to confirm the files are in iCloud.
Fix iCloud Photos when syncing is paused
For Photos, read the library status before changing settings. On iPhone or iPad, open Photos > Collections, tap the profile button in the upper corner, and read the status below your name and photo count. On iOS 17 or earlier, open Photos > Library > All Photos and scroll to the bottom.
On Mac, open Photos, select Library in the sidebar, click All Photos in the toolbar, and scroll to the bottom. If the status shows a slow or paused upload, connect the device to power and Wi-Fi and leave it uninterrupted overnight.
When Photos shows Optimizing Battery Power, Optimizing System Performance, or Poor Network Connection, tap Sync Now or wait for syncing to resume automatically.
For Low Power Mode, open Settings > Battery > Low Power Mode and turn it off. For Low Data Mode on Wi-Fi, open Settings > Wi-Fi, tap the active network, and turn off Low Data Mode; for cellular, the route depends on the plan. On LTE/4G, open Settings > Cellular (or Mobile Data) > Cellular Data Options and turn off Low Data Mode. On 5G, open Settings > Cellular > Cellular Data Options > Data Mode and turn off Low Data Mode. With Dual SIM, open Settings > Cellular or Mobile Data, tap the number for that line, and turn off Low Data Mode.
When the status points to battery, heat, or storage, charge above 20 percent, let the device cool down, or reduce iCloud storage use or upgrade the iCloud storage plan. Do not turn off iCloud Photos for stuck Photos syncing, because Apple says that restarts the syncing process.
If this method fails, open Photos and check for an Unable to Upload album. Edit each failed photo or video and check whether it uploads, or upload the item again from iPhone or iPad; on Mac, reimport failed items after confirming they use a supported type such as HEIF, JPEG, RAW, PNG, GIF, TIFF, HEVC, or MP4.
Repair Contacts, Calendar, and Reminders sync
In Contacts on iPhone or iPad, swipe down on the contact list to refresh it.
For contact groups, tap the back arrow or Lists, then swipe down on the list.
In Calendar on iPhone or iPad, tap Calendars and swipe down on the list.
In Contacts, tap Lists and select All iCloud so iCloud contacts are visible.
In Calendar, tap Calendars and select every iCloud calendar that you use.
For new contacts, open Settings > Apps > Contacts > Default Account > iCloud.
For new calendar events, open Settings > Apps > Calendar > Default Calendar and choose a calendar under iCloud.
For new reminders, open Settings > Apps > Reminders > Default List and choose a list under iCloud.
On Mac, open Calendar > View > Refresh Calendars.
On Mac, open Contacts > Contacts > Accounts, click iCloud, and confirm you are signed in and Contacts is turned on under Saved to iCloud.
In Reminders, open Today and complete or delete overdue reminders on each device using iCloud Reminders.
After each change, refresh the affected app again before checking another device.
Check Drive, Desktop, and Documents settings
The most common Drive and Desktop and Documents cause to rule out is iCloud Drive being off on one Mac or another cloud provider already managing those folders.
On Mac, open Apple menu > System Settings > [your name] > iCloud > Drive or iCloud Drive.
Turn on Sync this Mac, turn on Desktop & Documents Folders, and choose Done. Repeat this on every Mac that uses the feature.
If OneDrive, Dropbox, Google Drive, or another cloud provider syncs or manages Desktop and Documents, turn that provider's Desktop and Documents feature off before enabling Desktop & Documents Folders in iCloud.
On Windows, open iCloud for Windows, sign in, click the arrow button next to iCloud Drive, turn on iCloud Drive, and select Done.
If iCloud Drive reports a path that is too long, shorten one or more file or folder names, or move the file to a shorter folder path.
Fix iCloud for Windows and Outlook sync
Use this when iCloud is current on Apple devices, but Contacts, Calendars, Photos, Bookmarks, Drive, or Outlook data is stale on a Windows PC. Start by putting the Windows setup on Apple's current requirements.
Install or update iCloud for Windows from Apple's official download page through the Microsoft Store. Apple's latest recommended setup is Windows 11, iCloud for Windows 15, and Outlook 2021 or later when Outlook sync is used.
For Outlook Contacts and Calendars, open Outlook and click Refresh.
If that does not update the data, open iCloud for Windows, deselect Calendars and Contacts, choose Apply, wait a few seconds, select Calendars and Contacts again, choose Apply, then open Outlook.
If Outlook still is not syncing, close Outlook, open iCloud for Windows > Account Details > Sign Out, then sign back in with your Apple Account, select Calendars and Contacts, and choose Apply.
For connection or sign-in failures, set the correct Windows date, time, and time zone, use an administrative Windows account, update iCloud for Windows, update Windows, set up Windows Hello, and use one type of security software.
If Advanced Data Protection is on, use iCloud for Windows 14.1 or later. With iCloud for Windows 14.2 or later, keep a trusted Apple device within Bluetooth range of the PC or put both on the same Wi-Fi router; if a VPN is on, turn it off temporarily.
If Security Keys are added to the Apple Account, sign in on Windows with iCloud for Windows 15 or later.
For iCloud photos or videos that display incorrectly on Windows, open iCloud for Windows, deselect iCloud Photos and Shared Albums, choose Done > Apply > Delete from PC, then reselect iCloud Photos and Shared Albums, choose Done, and choose Apply.
Handle iCloud.com and managed account limits
When iCloud.com is the only place that does not show your data, start with web-access settings. On iOS or iPadOS 26.4 or later, open Settings > [your name] > iCloud > iCloud.com, then turn on Allow Data Access; turn on Allow Search only when you want search access too.
On earlier iOS or iPadOS versions, open Settings > [your name] > iCloud and turn on Access iCloud Data on the Web.
On macOS 26.4 or later, open Apple menu > System Settings > [your name] > iCloud > Data Access on iCloud.com, then turn on Allow Data Access.
On earlier macOS versions, open Apple menu > System Settings > [your name] > iCloud and turn on Access iCloud Data on the Web.
With Advanced Data Protection, turn on web data access, sign in to iCloud.com, then approve temporary access from a trusted device.
For a student Managed Apple Account showing Some iCloud Data Isn't Syncing, open the message in Settings, choose Resume Data Sync, and enter the requested current and previous device passcodes.
Managed Apple Accounts do not support iCloud for Windows, so reinstalling the Windows app does not change that limitation.
If this method fails, restart the affected device and check again after it reconnects to iCloud. On Mac, use Apple menu > Restart; on iPhone or iPad, hold the device's restart buttons until the power-off slider appears, drag the slider, wait 30 seconds, then turn the device back on until the Apple logo appears.
Frequently Asked Questions
Why is iCloud asking for my password again after I changed it?
Update the sign-in information for every iCloud service on the device. For a third-party app that accesses iCloud data, create and use an Apple app-specific password instead of your main Apple Account password.
What does Some iCloud Data Isn't Syncing mean on a student account?
A student Managed Apple Account needs passcode verification to resume encrypted iCloud data sync. If no previous device passcodes are available, Apple's flow can delete end-to-end encrypted iCloud data such as saved passwords, Safari bookmarks and history, Messages in iCloud, Maps history, and Memoji, while leaving iCloud Drive and other data categories.
Can I restore iCloud bookmarks that stopped syncing?
Deleted iCloud bookmarks can be restored within 30 days at iCloud.com/recovery under Restore Bookmarks. If that page shows No Bookmarks, Safari has not been turned on in iCloud settings on your devices.
Does Reset Network Settings fix iCloud not syncing?
No. Apple documents Reset Network Settings for network settings, but Apple does not present it as an iCloud sync repair step in its current iCloud troubleshooting paths.
