# Questions? We have answers.

## Summary

Learn about error code MBER1338 and how to resolve it.

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## Symptom

While [appending an account grouping](https://support.mindbridge.ai/hc/en-us/articles/360059962414), the following error message appears:

_You are attempting to append account code **{code}** to an account grouping that exists at the most granular level ( **{parentCode}**). To append an existing account grouping, select an account from a higher level._

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## What does this error mean?

A new entry cannot be added at a level underneath an existing, most granular code, as it may corrupt existing mappings.

In the example below `Current Assets.01.01` goes down to L3 and exists at the most granular level.

Attempts to add an L4 under an L3 that previously had a MAC code (row 6 in the screenshot below) would be a violation and would trigger an error.

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## Resolution

The new appending file must be updated so there are no entries at a level underneath an existing, most granular level.

In the above example both L2 and L3 can be added, but not an L4.