diff --git a/.travis.yml b/.travis.yml
index 7b986db..2d39559 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -53,6 +53,7 @@ install:
   - if [ -z "$dropPlatform" ]; then composer config --unset platform.php; fi;
   - if [ -z "$qaExtended" ]; then phpenv config-rm xdebug.ini || :; fi;
   - if [ -z "$dependencies" ]; then composer install --prefer-dist; fi;
+  - if [ "$dependencies" = "lowest" ]; then rm composer.lock vendor -Rfv; fi;
   - if [ "$dependencies" = "lowest" ]; then composer update --prefer-lowest --prefer-dist -n; fi;
   - if [ "$dependencies" = "highest" ]; then composer update --prefer-dist -n; fi;
   - composer show