When cloud storage stops syncing, protect unsynced work first. Copy any locally edited, unconfirmed files to a separate safe folder, then start a change log with the first bad time, affected account, device, exact error, and last confirmed good sync. Do not delete or reorganize the live sync folder while the cause is unknown.
Preserve evidence and define the scope
Record whether the problem affects one file, one folder, one account, one device, or every user. Check the provider's web interface: if the current file exists there, the local client may be behind; if it is missing from the web but exists locally, protect the local copy before reconnecting anything. Note file names, sizes, owners, permissions, timestamps, and client version without putting private file contents into a support log.
Google warns that files in Drive for desktop's Lost & Found can be lost when an account is disconnected, so its instructions say to copy them to a safe location first (Google Drive for desktop troubleshooting). This is an important check before using a tempting reset step.
Work through the dependency chain
Check service status, internet access, the signed-in account, cloud quota, local disk space, file permissions, file-name or size rules, and whether sync is paused. Google states that Drive for desktop needs enough local storage and documents internet, restart, reconnect, and reinstall steps for general failures. It also notes that system cleaner apps may edit configuration data and cause errors or data loss. Record each finding before taking action.
Microsoft's OneDrive guidance likewise routes sync failures through account, storage, icon, and client checks rather than treating every red indicator as the same problem (Microsoft OneDrive sync troubleshooting). Use the provider-specific error and icon meaning; do not assume a generic restart fixes an ownership or quota problem.
Change one thing at a time
Start with the least disruptive test: resume sync, restore connectivity, free enough local or cloud space, or correct a known permission. Then wait for a clearly defined file to sync. Add the action, time, old state, new state, and result to the change log. Only after preserving unsynced files should you disconnect an account, reinstall the client, or rebuild a sync location.
If one file fails, test a small neutral file in the same folder. If the neutral file succeeds, compare name, size, ownership, lock state, and permission. If all files fail on one device but succeed on the web and a second device, focus on the local client or operating-system boundary. If every device fails, check provider status, account policy, quota, and shared-folder ownership.
Verify recovery from both sides
Create or update a harmless test file locally, confirm it appears in the web interface, then make a second harmless change on the web and confirm it reaches the device. Open the file rather than relying only on a green icon. Recheck protected unsynced files, collaborators' access, and the next automatic sync cycle. Close the log with the root cause or label the result a workaround. Keep the preserved copy until the owner confirms that all intended changes exist in the cloud and on the required devices.
Sources
- Fix problems in Drive for desktop — Google Drive Help
- Fix OneDrive sync problems — Microsoft Support