"Processing changes" is the OneDrive sync app telling you it's still working through its queue. Usually it clears by itself; when it sits there for hours, something specific is holding it up: an open file, a huge file, too many items, a name OneDrive can't sync, or a sign-in problem. In this post I'll show how to find which one it is on a work or school PC, fix it without losing data, and prove the device is syncing again.
Errors this guide fixes
Processing changesOneDrive sync appProcessing 0KB of x MBOneDrive sync appSync pendingOneDrive sync appYour proxy settings require authenticationOneDrive sign-in0x8004de42OneDrive sign-in
Symptoms#
- The OneDrive cloud icon in the notification area shows
Processing changesfor hours, and new or edited files don't show up on the web or on other devices. - The status reads
Processing 0KB of x MBand the numbers never move. - Files stay on
Sync pending. - OneDrive asks the user to sign in again, or sign-in fails with
Your proxy settings require authenticationor error code0x8004de42. - In the OneDrive sync health dashboard, the device shows errors or an old "last synced" time.
Why it happens#
The sync app works through local and cloud changes as a queue, and the status stays on "Processing changes" until the queue is empty, so one stuck item keeps the status showing. The usual causes, from Microsoft's guidance and the documented sync limits:
| Cause | What's going on |
|---|---|
| A file is open | An app has the file open, so OneDrive can't finish uploading it |
| Lots of new or changed files | A bulk copy, a newly synced library, a fresh sign-in or a computer update means a lot of re-checking; slow internet makes it longer |
| A very large file | ZIP archives, long videos and Outlook PST or OST files take a long time; PST files also sync less often than other types |
| Too many items | Microsoft recommends no more than 300,000 items in total across your cloud storage; performance can suffer above that even if you don't sync every item |
| Names and file types it won't sync | Invalid characters, reserved names, temporary or hidden files, and file types your organization blocks |
| Sign-in or network | The user is signed out (often after a password change), or traffic goes through an authenticated proxy, which OneDrive doesn't support |
How to fix it#
1. See what OneDrive is working on#
Select the OneDrive cloud icon. The activity list shows files that are open, syncing or recently synced. If the same file keeps reappearing, start with that one: close it in its app (and close Outlook if a PST is involved), then watch whether the status moves. Leftover temporary or hidden files can also block sync, so look in the folder for files the user doesn't recognize.
2. Move big files out of the way#
Move Outlook data files out of the OneDrive folder and stop syncing folders that hold large videos or archives. Microsoft also notes that OneDrive log files named aria-debug can be deleted safely. To stop PSTs being uploaded across the organization, use the OneDrive policy Exclude specific kinds of files from being uploaded. If Known Folder Move was enabled by policy, PSTs in Documents move too and Outlook may then complain it can't find them; plan for that as described in OneDrive Known Folder Move with Intune.
3. Count the items#
In File Explorer, right-click the OneDrive folder and select Properties. If Contains is above 300,000 items, reduce what's synced: remove shortcuts added to My files, stop syncing SharePoint libraries the user doesn't need, and archive old content. Synced libraries live in a separate folder named after your organization, so count that too. Microsoft is previewing support for up to 1,000,000 items per sync instance on Windows, but only on devices that meet its hardware and Insiders-ring requirements; everything else stays at the 300,000-item supported limit.
4. Fix names and paths#
OneDrive won't sync names containing " * : < > ? / \ |, names with leading or trailing spaces, or the reserved names .lock, CON, PRN, AUX, NUL, COM0 to COM9, LPT0 to LPT9, desktop.ini, anything containing _vti_ and anything starting with ~$. A folder called forms can't sit at the root of a library, and .tmp files never sync. Windows already blocks those characters, so on a PC the usual culprits are spaces, reserved names and very deep paths. This lists suspect names and the longest paths:
$root = $env:OneDriveCommercial
$items = Get-ChildItem -LiteralPath $root -Recurse -Force -ErrorAction SilentlyContinue
# Names OneDrive won't sync
$items | Where-Object { $_.Name -ne $_.Name.Trim() -or $_.Name -like '*_vti_*' -or $_.Name -like '~$*' } |
Select-Object FullName
# The 20 longest paths
$items | Sort-Object { $_.FullName.Length } -Descending |
Select-Object -First 20 @{ n = 'Length'; e = { $_.FullName.Length } }, FullNameRename or move what it finds (press F2 to rename) and shorten deep folder structures.
5. Check sign-in and the proxy#
If the user changed their password, OneDrive may simply need them to sign in again. If sign-in fails with the proxy authentication message or 0x8004de42, the device is going through an authenticated proxy: let OneDrive and SharePoint traffic through without proxy authentication. For other sign-in codes, see the OneDrive sync error codes quick reference.
6. Pause and resume, then reset#
From the OneDrive icon, pause syncing (2, 8 or 24 hours), then resume it straight away. If the status still doesn't move, reset the sync app. A reset doesn't delete local or cloud files, but it disconnects every sync connection and rescans everything, so expect a long first sync on big accounts and re-select folders afterwards if you only synced some.
%localappdata%\Microsoft\OneDrive\onedrive.exe /reset
rem Per-machine installations use one of these paths instead
"C:\Program Files\Microsoft OneDrive\onedrive.exe" /reset
"C:\Program Files (x86)\Microsoft OneDrive\onedrive.exe" /resetIf OneDrive doesn't start again after a few minutes, start it from the Start menu. As a last resort, Microsoft's guidance is to unlink and relink the PC from OneDrive settings.
7. Find affected devices at scale#
The OneDrive sync health dashboard lives in the Microsoft 365 Apps admin center under Health › OneDrive Sync. It needs sync app 22.232 or later, a Tenant Association Key from the dashboard's Setup page, and reporting turned on for devices: in Intune, the settings catalog OneDrive settings Enable sync health reporting for OneDrive and Sync Admin Reports (paste the key there), or the EnableSyncAdminReports value set to 1 under HKLM\SOFTWARE\Policies\Microsoft\OneDrive. Data can take up to three days to appear. The Issues tab lists error messages with the number of devices affected, and the Devices tab shows each device's errors and last synced time.
Verify the fix#
- The OneDrive icon no longer shows "Processing changes" and the activity list stops cycling through the same files.
- A small test file created in the OneDrive folder appears in OneDrive on the web within a minute or two, and an edit made on the web comes back down to the PC.
- File Explorer's Status column shows no
Sync pendingitems in the folders you fixed. - In the sync health dashboard, the device's errors clear and its last synced timestamp is current. Devices report roughly every 36 hours, or about an hour after the sync app starts, so allow time.
Prevent it next time#
- Keep accounts under 300,000 items, and be selective with library syncs and shortcuts: both count.
- Keep PSTs and other bulky file types out of OneDrive with the upload exclusion policy, especially before you turn on Known Folder Move.
- Keep the sync app current on the Production or Deferred ring, and don't route OneDrive through an authenticated proxy.
- Turn on sync health reporting before a big rollout so you see stuck devices before users report them.
