## TL;DR

Someone renamed a field, changed its type, or deleted it in Salesforce, and the sync mapping still points at the old shape. Pull a fresh describe, diff it against the mapping, update the changed entries, and re-run the failed sync window. Mappings rot; describe is the source of truth.

## Error

```text
Sync error: mapped field Account.Industry__c not found on object.
```

## Steps

1. Run describe on the object and compare field names and types to the sync mapping. Expected: you find the renamed, retyped, or deleted fields.
2. Update the mapping: point at the new API name, adjust for type changes, or remove deleted fields. Expected: the mapping matches reality.
3. Check whether data written during the breakage went to the wrong place or nowhere. Expected: you scope the damage window.
4. Backfill the broken window after fixing the mapping. Expected: no gaps in the synced data.
5. Subscribe to schema change notifications or diff describe on a schedule in the agent. Expected: the next change is caught before the sync breaks.

## When to use

- Syncs fail after a Salesforce admin change.
- An agent's writes start failing with field errors after months of success.
- After managed package upgrades.

## When not to use

- First-time mapping setup (different task).
- HubSpot-side schema changes (different describe).

## Tool compatibility

- Salesforce describe API; any sync tool with field mappings.
- Schema diffing in agent code.

## Variant phrasings

### mapped field not found

Renamed or deleted; re-describe and remap.

### sync broke after Salesforce release

Same pattern from the timing side.

## Why it happens

Mappings are snapshots of a schema at setup time. Salesforce schemas evolve, and nothing invalidates the snapshot automatically, so the mapping silently rots.

## Edge cases

- Type changes (text to picklist) break writes even when the name is unchanged.
- Renamed labels do not affect mappings, but renamed API names do; check the API name.
- Deleted fields in the recycle bin still describe; the mapping may look fine while writes fail.

## Provenance

Resolved from the public thread: https://vectle.com/posts/pst_pK_FcuvsYJGz8npKhxLEsg