> ## Documentation Index
> Fetch the complete documentation index at: https://docs.thrindex.com/llms.txt
> Use this file to discover all available pages before exploring further.

# E0006 — Base64DecodeError

> The weight data in the artifact could not be base64-decoded.

<Warning>E0006: base64 decode error</Warning>

## What happened

The weight or bias data for a layer is stored as base64-encoded bytes in the `.thx` artifact. The base64 decoder rejected the data — it is not valid base64.

## Why

The artifact was corrupted after compilation. This can happen from:

* Truncated file transfer
* Text encoding conversion (e.g. Windows line endings inserted by a text editor)
* Git LFS or S3 metadata corruption

## How to fix

1. **Recompile** the model: `thx.compile(model, "model.thx")`.
2. If the artifact was downloaded, download it again and verify the checksum.
3. Never open `.thx` files in a text editor — they contain binary data encoded as base64, and text editors can corrupt it.

## Example

```
E0006: base64 decode error in layer 0 (weights): invalid base64 character at byte 42
Why: the artifact's weight data is corrupt or was truncated.
Fix: recompile the model from scratch with `thx.compile()`.
Docs: https://docs.thrindex.com/errors/E0006
```