title: Mysql not starting in a docker container on MacOS after docker update
body: <p>I just upgraded to Docker Desktop 2.4 on MacOS, from version 2.3. Suddenly none of my mysql containers will start. The logs show this as the reason:</p>
  <pre><code>Different lower_case_table_names settings for server ('2') and data dictionary ('0').
  Data Dictionary initialization failed.
  Aborting
  </code></pre>
  <p>The database files are mounted in a volume on my host machine, so that they persist between restarts.</p>
  <p>I finally figured out why. Posting in order to answer.</p>