OneDrive Not Syncing? How to Fix It Step by Step

There are few things more unnerving than seeing OneDrive stuck on Processing changes or Sync pending when you need a file on another device. Usually nothing is lost, it's just stuck behind something. Microsoft's own troubleshooting points to a handful of common culprits. Work through them in this order and most sync problems clear up in minutes.

Step 1: Check what OneDrive is telling you

Click the OneDrive cloud icon by the clock (or in the menu bar on a Mac). The panel shows files that are open, syncing or recently synced, plus any error. A red cross or warning usually names the file causing trouble, which saves you guessing.

The common causes and fixes

What's happening	What to do
A OneDrive file is open	Close it once you've finished editing
You added lots of files	Wait; it uploads everything, just slowly on a slow connection
A very large file, like a ZIP, long video or Outlook PST or OST file	Move it out of OneDrive or stop syncing that folder
You're signed out	Sign in again, especially after a password change
You've just signed in or updated your computer	Wait; it re-syncs everything in time
Hidden or temporary files	Show hidden items and deal with them

Every row comes from Microsoft's own list. The large-file row is the one I see most in small businesses: an Outlook data file sitting inside a synced folder changes constantly, so OneDrive never finishes. Move it out of OneDrive and the queue clears.

Step 2: Run a speed test

If you've added a lot of files, Microsoft says no action is needed, but it may take some time if your internet is slow, and it suggests running an internet speed test to check the problem isn't elsewhere. If your upload speed is tiny, OneDrive isn't broken; your connection is the bottleneck.

Step 3: Fix Sync pending with nothing visible

If a folder says Sync pending but you can't see a file causing it, Microsoft says it could be a hidden file. In File Explorer, go to View and turn on Hidden items. If there's nothing hidden either, create a new folder, copy everything from the stuck folder into it, then delete the stuck one. One oddity worth knowing: Microsoft notes that empty folders may show Sync pending until you put a file in them, so an empty folder isn't necessarily a problem.

Step 4: Watch out for temporary files

Anything ending in .TMP can hold up sync. Microsoft suggests uploading them manually, renaming them, moving them out of OneDrive, or deleting them. Be careful with the last option: Microsoft recommends you don't delete TMP files unless you're sure they're no longer in use, because you could lose unsaved work.

Step 5: Check your file names and paths

Windows has a path length limit that trips people up with deeply nested folders. Microsoft says the entire file path, including the file name, must be fewer than 260 characters. If you have folders inside folders inside folders with long names, shorten a few names or move the file closer to the top.

Step 6: Unlink and re-link OneDrive

If nothing else works, this is Microsoft's go-to reset, and it says no data will be lost: your local folders are simply disconnected from the cloud for a short while, and changes you make in the meantime sync once you re-link.

1. Click the OneDrive cloud icon, then Help and Settings, then Settings.
2. On the Account tab, select Unlink this PC, then Unlink account.
3. Sign in again when prompted.
4. When OneDrive says the folder already exists, choose Use this folder.

Microsoft also describes clearing the stored sign-in details on Windows: press the Windows key and R, go to the folder %localappdata%\Microsoft\OneDrive\settings and delete the file named PreSignInSettingsConfig.json before signing in again. On a Mac, the equivalent is removing the OneDrive entry in Keychain Access.

OneDrive on a Mac

On Apple computers you get the same fixes with slightly different menus. The OneDrive icon lives in the menu bar rather than by the clock, and you unlink from Preferences on the Account tab. Microsoft also notes that after some macOS updates, Processing changes can show for a long time and simply needs waiting out.

If it's still not syncing

Resetting or reinstalling the app is the next step, and I've written a separate guide on uninstalling and reinstalling OneDrive. It's also worth asking whether OneDrive is the right home for everything you're syncing. Huge video archives and constantly changing data files are better kept elsewhere. If you're weighing up options, my piece on the benefits of cloud hosting is a good primer, and this guide to freeing up Google Drive space helps if you're splitting files between services.

My verdict

Close open files, sign back in, move huge files like Outlook data out of OneDrive, and give big uploads time. Show hidden items for stubborn Sync pending folders and keep paths under 260 characters. When all else fails, unlink and re-link, which Microsoft says loses nothing.

Frequently asked questions

Why is OneDrive stuck on Processing changes?

Microsoft lists open files, lots of new files, very large files, being signed out, or a recent sign-in or update as common causes.

Will unlinking OneDrive delete my files?

No. Microsoft says no data is lost by unlinking and re-linking. Your folders are just disconnected for a short while.

Why does an empty folder say Sync pending?

Microsoft notes empty folders may show Sync pending until you put a file in them.

Can Outlook files stop OneDrive syncing?

Yes. Large Outlook PST or OST data files can hold up sync. Move them out of your OneDrive folders.

What is the file path limit for OneDrive on Windows?

Microsoft says the entire path, including the file name, must be fewer than 260 characters.