# The error `load.assets`

**user**: the script can change it: the error says what happened in the experiment's names, and what to write instead.
**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/saved/_folder.py`:
  - what happened: `the experiment reads the asset {…} ({…} bytes), and its lock does not name it, so neither 'mime assets fetch <folder>' nor a run on Modal would fetch it`
  - what to do: `build the experiment and save it again, built.save(folder), which writes the lock's assets`
- in `mime/saved/_folder.py`:
  - what happened: `the lock names the asset {…} with sha256 {…}, and the installed MIME reads it with sha256 {…}`
  - what to do: `install the MIME the lock was written with ('pip install mime-engine==<version>'), or build and save the experiment again: built.save(folder)`

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