Symptoms
- OneDrive icon in the taskbar shows a red X or exclamation mark
- Files show as 'not synced' or the sync indicator is stuck for hours
- Some files sync while others don't move at all
- Message about exceeding storage limit
Likely causes
- CommonOneDrive sync is paused or signed outThis can happen after a Windows update or manual pause that was forgotten.
- CommonAccount storage quota is fullFree and paid plans both have limits that stop new uploads once reached.
- PossibleA specific file has an invalid character, is too large, or is open in another programA single problem file can block the whole sync queue behind it.
- PossibleInternet connection is unstable or OneDrive service is downCheck Microsoft's service status if sync stalls broadly.
- PossibleLocal OneDrive cache or database is corruptedThis can cause persistent stuck syncs that resist simple fixes.
What to do
- Click the OneDrive icon in the system tray and check its status and any error messages.
- Confirm you're signed in and sync isn't manually paused.
- Check your account's storage usage on the OneDrive website to rule out a full quota.
- Look for a specific file causing a stall, often flagged with a warning icon, and rename or move it if it has unusual characters.
- Check Microsoft 365 service status for a known outage.
- As a last resort, unlink and relink the OneDrive account, which resets the sync without deleting cloud files.
When to call a pro
If unlinking and relinking doesn't fix persistent sync failures, Microsoft support or an IT professional can check account-level sync issues.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.