OneDrive stuck on “Processing changes” for hours

You look at the taskbar and the OneDrive cloud has been showing the same message for hours:

Processing changes

In File Explorer some files and folders show the two blue arrows chasing each other in a circle, and they never turn into a green tick. Nothing else says what is wrong. Sometimes the message is “Processing 0KB of x MB” instead. The sync app is not necessarily broken. It is either still working through a very large pile of changes, or it is stuck on something it cannot sync. This article shows you how to tell which, and how to fix it without risking your files.

Applies to: the OneDrive sync app on Windows 10 and Windows 11, for personal OneDrive and for work or school accounts, including SharePoint libraries you sync to your PC. The Mac app has its own reset and is not covered here.

What is going on

Microsoft documents “Processing changes” as the status you see while the sync app uploads, downloads or moves a large number of files. So the message on its own is not an error. It becomes a problem when it never ends. Microsoft names a few things that make that happen:

• Too many items. Microsoft recommends syncing no more than about 300,000 items in total (files and folders, not gigabytes), and says performance problems can start above that even if you are not syncing all of them. A Git repository, an unzipped code base or a photo archive can reach that quickly.
• Names that OneDrive does not allow. Characters such as " * : < > ? / \ |, leading or trailing spaces, reserved names such as CON, PRN, AUX, NUL, desktop.ini, .lock, anything starting with ~$, and paths that are too long, can stop a file or folder syncing.
• A full OneDrive. If the account is out of storage, the app cannot upload new files.
• An old sync app. Microsoft tells you to update to the current build before troubleshooting further.
• Conflicts. Two versions of the same file (for example, edited offline on two PCs) can leave a sync icon sitting on a file.

The research behind this article also claimed that a hidden local database “gets into an infinite loop” and that Office lock files such as ~$document.docx cause it. I could not find either in Microsoft’s documentation, so neither is presented as fact here. What Microsoft does say about ~$ files is that they are not allowed in OneDrive, which means they are skipped rather than synced.

Diagnosis

1. Decide whether it is stuck or just busy

Think about what happened just before it started. If you copied, unzipped or moved thousands of files into the OneDrive folder, or you connected a big SharePoint library, then “Processing changes” can legitimately last a long time. Check the CPU and network use in Task Manager. If OneDrive is still using either, it is working. If it has been idle for an hour with the same message, it is stuck.

2. Count your items

Open File Explorer, right-click the OneDrive folder and choose Properties. The Contains line shows the number of files and folders. Microsoft says to consider reducing the number if it is above 300,000. Folders you have added as shortcuts, and SharePoint libraries you sync, count towards the total, and Microsoft notes that removing shortcuts and stopping the sync of libraries you do not need are both effective.

3. Look for files that need attention

Click the OneDrive cloud icon in the notification area (you may have to click the little up arrow to find it). If there are files it cannot sync, the pop-up lists them and says why. In File Explorer, a sync icon that stays on one file that is not actively syncing usually means a conflict that you have to resolve. For Office files, opening the file in the Office app starts the conflict options (save a copy, or discard your change). For other file types OneDrive keeps both versions and adds your device name to the copy, so you can keep, rename or merge them.

4. Check names and paths

Compare the names of the files it is stuck on with the list above. Rename anything with a forbidden character, a trailing space or a reserved name. To rename in File Explorer, select the item and press F2. A very long path can also stop a file syncing: shorten the folder names above it.

5. Check storage and updates

Sign in to OneDrive on the web and look at how much storage you have left. Then check that the drive that holds your OneDrive folder has free space. Finally, in Settings, Apps, Installed apps, find Microsoft OneDrive and check you are on a current version; installing the latest sync app over it is safe.

Root cause

There is no single cause, and I do not want to invent one. In practice it is one of: a very large number of items that simply takes a long time to process, a file or folder with a name or path OneDrive will not accept, a conflict or a file that stays locked by another program, a full OneDrive, or an out-of-date or confused sync app. The steps below go from the least to the most disruptive, so you stop as soon as it clears.

The fix

Step 1: Pause and resume

Click the OneDrive cloud icon, choose More, then Pause syncing and pick 2 hours. Wait about 15 seconds, then choose More again and Resume syncing. Microsoft suggests this for a sync that is already in progress and not moving.

Step 2: Close what has the files open

Close Word, Excel, Outlook, PDF viewers and anything else that might have a file from the OneDrive folder open, then pause and resume once more. If you keep Outlook .pst files in OneDrive, consider moving them out; Microsoft says they are synced less often than other files and publishes steps for removing a PST file from OneDrive.

Step 3: Reduce the load

If you counted more than 300,000 items, use Choose folders in the OneDrive settings to stop syncing folders you do not need on this PC, or turn on Files On-Demand so files are not all downloaded. Microsoft recommends both for large libraries. Do this before the reset, because a reset will otherwise just start the same large job again.

Step 4: Reset the sync app

This does not delete your files. Microsoft states that resetting OneDrive does not lose files or data. It disconnects the sync connections (personal and work or school), clears the sync app’s local state, and rebuilds it. OneDrive then does a full check of everything, which is slow on a big library.

Press the Windows key and R together, paste the line below and press OK:

%localappdata%\Microsoft\OneDrive\onedrive.exe /reset

If Windows says it cannot find the file, try these two in turn:

C:\Program Files\Microsoft OneDrive\onedrive.exe /reset
C:\Program Files (x86)\Microsoft OneDrive\onedrive.exe /reset

If none of the three works, you probably do not have the desktop sync app installed. The reset opens nothing visible. The OneDrive icon may disappear for a minute or two. Then start OneDrive yourself from the Start menu (type OneDrive); Microsoft’s instructions tell you to restart it manually, so do not wait for it to come back by itself. Sign in if asked and let it finish its check.

If you had chosen to sync only some folders, that choice is lost in the reset. Pick them again once the first sync is finished, for each account you use.

Step 5: Unlink and sign in again

If it is still stuck, click the cloud icon, open Settings, go to the Account tab and choose Unlink this PC. Sign in again with the same account. When it asks where to put the OneDrive folder, choose the existing folder, so files that have not changed do not have to be downloaded again. Microsoft documents the same idea for the Mac reset, and for libraries it says that stopping a sync just disconnects the folder, with the files kept in both places.

As a final option Microsoft lists uninstalling and reinstalling the OneDrive app. Your files stay on OneDrive online.

Do not move or copy files back and forth between folders while OneDrive is processing. Doing that while the sync engine is busy is how you get duplicates and conflict copies named after your PC (for example Report-LAPTOP01.docx). Also do not delete the OneDrive folder or its contents to “start clean” unless you have checked on OneDrive.com that everything is there.

Verification

The cloud icon should briefly say it is looking for changes, then settle on Up to date without a sync badge. In File Explorer the files show a green tick or a cloud, not the blue circle. As a test, create a small text file in the OneDrive folder and check that it appears on OneDrive.com within a minute or two, then rename it on the web and watch the name change on your PC.

Notes

• For the biggest libraries, Microsoft has a public preview of syncing up to 1,000,000 items on Windows 11 and Windows Server 2022 with strict hardware requirements (SSD, 16 GB RAM or more). Outside that preview the supported figure is 300,000. Check Microsoft’s current documentation before relying on it.
• In a managed organisation, the better fix for a recurring problem is usually to split the biggest libraries into smaller ones and to exclude archive folders from syncing, rather than resetting users’ PCs again and again.
• Work or school accounts also have Microsoft’s Support and Recovery Assistant, which can diagnose OneDrive for work or school sync problems.
• Antivirus or endpoint protection that scans the OneDrive folder in real time is a reported cause of slow sync in Microsoft community answers, but I did not find it in the official documentation, so treat it as a lead to check, not a rule.

Still stuck after the unlink? Post what the OneDrive pop-up says, whether it is a personal or work account, and roughly how many files are in the folder in The Patch Panel and we will work through it. The best answer earns points on Top of the Stack.