diff --git a/backup.sh b/backup.sh
index 62bb8728bb10fd39bc9c7f7c46864df9ef8caeb0..5998c037006af97312a37579056553aaa32aec82 100755
--- a/backup.sh
+++ b/backup.sh
@@ -16,7 +16,7 @@ exit_on_fail(){
 retrie_on_fail(){
     if [ $1 -ne 0 ]; then
         backup "cleaned"
-        run_duplicity remove-all-inc-of-but-n-full 1 --force
+        run_duplicity remove-all-inc-of-but-n-full $(($BK_KEEP_FULL-1)) --force
         leave $?
     fi
 }