OneDrive File Issues

How to Fix OneDrive Personal Vault Sync Errors and Red X Messages

Steve K Oct 1, 2026 868 views

Question details

The user needs to resolve synchronization failures within their OneDrive Personal Vault, indicated by an error message about unsupported item names or types.

How to Fix OneDrive Personal Vault Sync Errors and Red X Messages

Product: Microsoft OneDrive
Device & OS: not provided
Scenario: Attempting to sync or upload files securely to the OneDrive Personal Vault folder.
Observed behavior: The Personal Vault displays a red X icon and stops syncing, returning an error message stating that an item name or type is not allowed.

Before you start

Ensure your device has a stable internet connection and that the OneDrive application is currently running in your system tray or menu bar before troubleshooting sync errors.

Solution 1Recommended

Identify and Rename Unsupported File Names or Types

Fix the 'item name or type is not allowed' error by removing invalid characters from the files stored in your Personal Vault.

OneDrive has specific restrictions on file names and types. If you place a file with unsupported characters or an invalid format into the Personal Vault, the synchronization process will halt, displaying a red X.

Unlock Personal Vault

Open your OneDrive folder and double-click the Personal Vault icon to unlock it using your designated authentication method.

Locate problem files

Look for files that have a red X sync error icon next to them. Check their names for forbidden characters such as ", *, <, >, ?, |, :, or trailing spaces.

Rename or remove files

Right-click the problematic file and select 'Rename' to remove the invalid characters. Alternatively, move the file out of the Personal Vault to see if the sync error clears.

Identify and Rename Unsupported File Names or Types

File Types Limitation: Certain system files, temporary files, or files ignored by Windows (like desktop.ini) cannot be synced and will trigger this error if manually placed in the Vault.

Solution 2

Unlink and Relink Your OneDrive Account

If checking file names doesn't work, unlinking and reconnecting your account can refresh the connection and force a new sync.

Solution 3

Reset the OneDrive Application

Resetting the app clears the local sync cache, which can resolve persistent synchronization bugs without losing your data.

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Frequently Asked Questions

Why does my OneDrive Personal Vault show a red X icon?

A red X indicates a synchronization error. In the Personal Vault, this usually happens because a file or folder contains unsupported characters in its name, is an invalid file type, or the local OneDrive sync client requires a reset.

Which characters are not allowed in OneDrive file names?

OneDrive does not support file names that contain characters such as " * : < > ? / \ | or names that start or end with a space. Ensure your files are free of these symbols before moving them to your Personal Vault.

Will I lose my files if I reset or unlink the OneDrive app?

No, resetting or unlinking OneDrive will not delete or alter your files. It simply severs the local connection or clears the temporary sync cache on your device. Your files remain safely stored online in your Microsoft cloud account.

Document & File Issues