diff --git a/build/entrypoint.sh b/build/entrypoint.sh
index 403ace6..73e6c80 100644
--- a/build/entrypoint.sh
+++ b/build/entrypoint.sh
@@ -22,6 +22,13 @@ else
     # delete lock files if they exist - this can happen if the container is restarted forcefully
     find $HOME -name "*.lock" -delete
 
+    # give friendly error if you don't have protonmail data
+    find $HOME | grep -q . || echo "No files found - start the container with the init command, or copy/mount files into it at $HOME first. Sleeping 5 minutes before exiting so you have time to copy the files over." && sleep 300 && exit 1
+    # give friendly error if the user doesn't own the data
+    if [[ $(id -u) != 0 ]]; then
+        find $HOME -not -user $(id -u) | grep -q . || echo "You do not own the data in $HOME. Please chown it to $(id -u), run the container as the owner of the data or run the container as root." && exit 1
+    fi
+
     # socat will make the conn appear to come from 127.0.0.1
     # ProtonMail Bridge currently expects that.
     # It also allows us to bind to the real ports :)
diff --git a/deb/entrypoint.sh b/deb/entrypoint.sh
index 241f32f..41fcf41 100644
--- a/deb/entrypoint.sh
+++ b/deb/entrypoint.sh
@@ -37,6 +37,13 @@ else
     # delete lock files if they exist - this can happen if the container is restarted forcefully
     find $HOME -name "*.lock" -delete
 
+    # give friendly error if you don't have protonmail data
+    find $HOME | grep -q . || echo "No files found - start the container with the init command, or copy/mount files into it at $HOME first. Sleeping 5 minutes before exiting so you have time to copy the files over." && sleep 300 && exit 1
+    # give friendly error if the user doesn't own the data
+    if [[ $(id -u) != 0 ]]; then
+        find $HOME -not -user $(id -u) | grep -q . || echo "You do not own the data in $HOME. Please chown it to $(id -u), run the container as the owner of the data or run the container as root." && exit 1
+    fi
+
     # socat will make the conn appear to come from 127.0.0.1
     # ProtonMail Bridge currently expects that.
     # It also allows us to bind to the real ports :)