# The error `asset.conflict`

**environment**: something the run needs is missing or different where it runs (a package, a file, a device, the network): the error names what to install, fetch or attach.

Where MIME gives it, with what its message says happened and what its action says to do (`{…}` is filled in from the experiment):

- in `mime/assets/_sources.py`:
  - what happened: `two installed sources hold the asset {…} {…} ({…}), and nothing pins one`
  - what to do: `pin the one the experiment is written against, AssetRef(..., sha256=...) declared in the script or kept in its saved lock; or uninstall the package whose record is wrong`

Reading an error and reaching its full traceback: [reading an error](../reading_errors.md). Every code: [the index](index.md).