diff --git a/README.md b/README.md
index b9f7a66d..c012608d 100644
--- a/README.md
+++ b/README.md
@@ -132,7 +132,7 @@ __PostgreSQL__:
 - `POSTGRES_PASSWORD` Password for the database user using postgres.
 - `POSTGRES_HOST` Hostname of the database server using postgres.
 
-As an alternative to passing sensitive information via environment variables, `_FILE` may be appended to the previously listed environment variables, causing the initialization script to load the values for those variables from files present in the container. See [Docker secrets](#docker-secrets) section below.
+As an alternative to passing sensitive information via environment variables, `_FILE` may be appended to the previously listed environment variables (except for `POSTGRES_HOST` and `MYSQL_HOST`, which cannot be loaded from files), , causing the initialization script to load the values for those variables from files present in the container. See [Docker secrets](#docker-secrets) section below.
 
 If you set any group of values (i.e. all of `MYSQL_DATABASE`, `MYSQL_USER`, `MYSQL_PASSWORD`, `MYSQL_HOST`), they will not be asked in the install page on first run. With a complete configuration by using all variables for your database type, you can additionally configure your Nextcloud instance by setting admin user and password (only works if you set both):
 
@@ -448,7 +448,7 @@ secrets:
 
 Currently, this is only supported for `NEXTCLOUD_ADMIN_PASSWORD`, `NEXTCLOUD_ADMIN_USER`, `MYSQL_DATABASE`, `MYSQL_PASSWORD`, `MYSQL_USER`, `POSTGRES_DB`, `POSTGRES_PASSWORD`, `POSTGRES_USER`, `REDIS_HOST_PASSWORD`, `SMTP_PASSWORD`, `OBJECTSTORE_S3_KEY`, and `OBJECTSTORE_S3_SECRET`.
 
-If you set any group of values (i.e. all of `MYSQL_DATABASE_FILE`, `MYSQL_USER_FILE`, `MYSQL_PASSWORD_FILE`, `MYSQL_HOST`), the script will not use the corresponding group of environment variables (`MYSQL_DATABASE`, `MYSQL_USER`, `MYSQL_PASSWORD`, `MYSQL_HOST`).
+If you set any group of values (i.e. all of `MYSQL_DATABASE_FILE`, `MYSQL_USER_FILE`, `MYSQL_PASSWORD_FILE`), the script will not use the corresponding group of environment variables (`MYSQL_DATABASE`, `MYSQL_USER`, `MYSQL_PASSWORD`).
 
 # Make your Nextcloud available from the internet
 Until here, your Nextcloud is just available from your docker host. If you want your Nextcloud available from the internet adding SSL encryption is mandatory.
diff --git a/docker-entrypoint.sh b/docker-entrypoint.sh
index 8e178f2e..87336074 100755
--- a/docker-entrypoint.sh
+++ b/docker-entrypoint.sh
@@ -207,12 +207,20 @@ if expr "$1" : "apache" 1>/dev/null || [ "$1" = "php-fpm" ] || [ "${NEXTCLOUD_UP
                         # shellcheck disable=SC2016
                         install_options=$install_options' --database-name "$SQLITE_DATABASE"'
                         install=true
-                    elif [ -n "${MYSQL_DATABASE+x}" ] && [ -n "${MYSQL_USER+x}" ] && [ -n "${MYSQL_PASSWORD+x}" ] && [ -n "${MYSQL_HOST+x}" ]; then
+                    elif [ -n "${MYSQL_DATABASE+x}" ] && [ -n "${MYSQL_USER+x}" ] && [ -n "${MYSQL_PASSWORD+x}" ]; then
+                        if [ -z "${MYSQL_HOST}" ] ; then
+                            echo "MySQL credentials set but no MySQL host set. Please make sure \$MYSQL_HOST is set."
+                            exit 1
+                        fi
                         echo "Installing with MySQL database"
                         # shellcheck disable=SC2016
                         install_options=$install_options' --database mysql --database-name "$MYSQL_DATABASE" --database-user "$MYSQL_USER" --database-pass "$MYSQL_PASSWORD" --database-host "$MYSQL_HOST"'
                         install=true
-                    elif [ -n "${POSTGRES_DB+x}" ] && [ -n "${POSTGRES_USER+x}" ] && [ -n "${POSTGRES_PASSWORD+x}" ] && [ -n "${POSTGRES_HOST+x}" ]; then
+                    elif [ -n "${POSTGRES_DB+x}" ] && [ -n "${POSTGRES_USER+x}" ] && [ -n "${POSTGRES_PASSWORD+x}" ]; then
+                        if [ -z "${POSTGRES_HOST}" ] ; then
+                            echo "PostgreSQL credentials set but no PostgreSQL host set. Please make sure \$POSTGRES_HOST is set."
+                            exit 1
+                        fi
                         echo "Installing with PostgreSQL database"
                         # shellcheck disable=SC2016
                         install_options=$install_options' --database pgsql --database-name "$POSTGRES_DB" --database-user "$POSTGRES_USER" --database-pass "$POSTGRES_PASSWORD" --database-host "$POSTGRES_HOST"'