# `package.digest_mismatch`

Installed package's files differ from its digest in the lock.

Area 11, [External services](../topics/external-services.md); not declinable; the next step is usually the human's.

An installed package is read-only: its files are what its digest in the
lock says:



```jadpo
// Generated by Jadpo from the installed packages; update it with `jadpo package add`, `update` or `remove`, never by hand.
record lock 1

package Postcodes.v2 version 2.1.0 path ../postcodes digest sha256:0000000000000000000000000000000000000000000000000000000000000000
```

```text
error: Package `Postcodes.v2` differs from what was installed
 --> packages/postcodes/v2/package.jadpo
  reason: An installed package is read-only: `jadpo.lock` locks it with digest `sha256:0000000000000000000000000000000000000000000000000000000000000000`, and its files now give `sha256:fc196456d53ad674b39fbab39eca4883d512f52feb90d687d22c2eeb2c9721e7`, so a file in `packages/postcodes/v2/` was changed, added or removed since it was installed.
  next: Restore `packages/postcodes/v2/` from version control, or install the package again with `jadpo package add`; change the app's own code instead (human)
  rule: package.digest_mismatch
  help: https://jadpo.dev/docs/errors/package.digest_mismatch

check failed: 1 error, 2 files
```