title: How to clear docker build cache (keeps saying 0B reclaimed)
body: <p>I just ran <code>docker buildx build</code> and it ran for about 10 minutes, but yet when I try to clear the build cache, it keeps saying that 0B was reclaimed. I'm obviously misunderstanding something here.</p>
  <p>Here's my total output:</p>
  <pre><code>ubuntu@ip-10-20-65-45:~$ docker buildx build --platform linux/arm/v7 .
  WARN[0000] No output specified for docker-container driver. Build result will only remain in the build cache. To push result image into registry use --push or to load image into docker use --load
  [+] Building 6000.2s (5/5) FINISHED
   =&gt; [internal] load build definition from Dockerfile                                                                                                                                                                                                                                                                                                                   0.1s
   =&gt; =&gt; transferring dockerfile: 32B                                                                                                                                                                                                                                                                                                                                    0.0s
   =&gt; [internal] load .dockerignore                                                                                                                                                                                                                                                                                                                                      0.0s
   =&gt; =&gt; transferring context: 2B                                                                                                                                                                                                                                                                                                                                        0.0s
   =&gt; [internal] load metadata for docker.io/kalilinux/kali-rolling:latest                                                                                                                                                                                                                                                                                               1.1s
   =&gt; CACHED [1/2] FROM docker.io/kalilinux/kali-rolling@sha256:8ce5177e07c182e6635cf303f8e3daceface00f0f40b27c34ab033cfb49bcbbd                                                                                                                                                                                                                                         0.0s
   =&gt; =&gt; resolve docker.io/kalilinux/kali-rolling@sha256:8ce5177e07c182e6635cf303f8e3daceface00f0f40b27c34ab033cfb49bcbbd                                                                                                                                                                                                                                                0.0s
   =&gt; [2/2] RUN apt update &amp;&amp;     apt dist-upgrade -y -o Dpkg::Options::=&quot;--force-confdef&quot; -o Dpkg::Options::=&quot;--force-confold&quot; &amp;&amp;     apt autoremove -y &amp;&amp;     apt clean -y &amp;&amp;     if [ &quot;linux/arm/v7&quot; = &quot;linux/arm/v7&quot; ] ; then     apt install wget -y &amp;&amp;     wget http://ftp.us.debian.org/debian/pool/main/libs/libseccomp/libseccomp2_2.5.1-1_armhf.deb -O lib  5999.0s
  ubuntu@ip-10-20-65-45:~$ docker builder prune
  WARNING! This will remove all dangling build cache. Are you sure you want to continue? [y/N] y
  Total reclaimed space: 0B
  ubuntu@ip-10-20-65-45:~$ docker build prune
  unable to prepare context: path &quot;prune&quot; not found
  ubuntu@ip-10-20-65-45:~$ docker image ls -a
  REPOSITORY      TAG               IMAGE ID       CREATED       SIZE
  moby/buildkit   buildx-stable-1   cf14c5e88c0e   2 weeks ago   123MB
  ubuntu@ip-10-20-65-45:~$ docker builder prune -a
  WARNING! This will remove all build cache. Are you sure you want to continue? [y/N] y
  Total reclaimed space: 0B
  ubuntu@ip-10-20-65-45:~$ docker builder prune -af
  Total reclaimed space: 0B
  ubuntu@ip-10-20-65-45:~$ docker buildx prune -af
  ID                                                                      RECLAIMABLE     SIZE    LAST ACCESSED
  r9fb1b3q8jmu7ann44vvjtpi5*                                              true            4.10kB
  xiw6rtbwe2xtd9s8xghdgcz70                                               true            154.88MB
  Total:  154.88MB
  ubuntu@ip-10-20-65-45:~$
  </code></pre>
  <p>The most I was able to get back was 154MB, but I know these images are much bigger than this. How do I properly clear out the cache from <code>docker buildx build</code>?</p>