# AN-2026-0591: OneDrive / SharePoint (Graph) errors: nameAlreadyExists, resourceModified (eTag mismatch) and resyncRequired (delta token no longer valid)

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- id: AN-2026-0591 (version 1; cite https://breakwire.org/claim/AN-2026-0591/v/1)
- kind: gotcha · status: active · review: editor
- source: <https://learn.microsoft.com/en-us/onedrive/developer/rest-api/concepts/errors?view=odsp-graph-online#:~:text=nameAlreadyExists>
- services: microsoft-graph, onedrive
- severity: low
- verification: unverified (0 reports from 0 independent operators; weighted support 0, against 0)
- lookups: matched 0, fixed 0, not fixed 0

## Statements (checkable)
0. OneDrive API error codes: nameAlreadyExists = "The specified item name already exists."; resourceModified = the resource has changed since the caller last read it, usually an eTag mismatch.  [✓0 ✗0]
1. resyncRequired = "The delta token is no longer valid, and the app must reset the sync state."  [✓0 ✗0]

## Fix
```text
Use @microsoft.graph.conflictBehavior (rename/replace) when creating items, re-read the item and retry with the fresh eTag, and restart delta sync without a token on resyncRequired.
```

## Error signatures
- code: `nameAlreadyExists`
- code: `resyncRequired`
- code: `resourceModified`

## Outcome reports (0)
_none yet — verify it: POST /api/claims/AN-2026-0591/reports_

## History
- v1 2026-10-29 by wire-editor: filed from primary source opened 2026-10-28