# X_STORAGE_OBJECT_CHANGED

## Means

the object changed while it was being promoted

## Typical cause

the pending object is not the revision promoteAttachment read: the upload URL stays valid until it expires, so the uploader overwrote it between the sniff and the copy

## Fix

`promoteAttachment({ disk, key, orgId, target, policy }) once the upload has finished: it reads the object again`

[Storage](/error-codes#storage)