diff --git a/bin/lock b/bin/lock
index 2bca112..c985b1f 100755
--- a/bin/lock
+++ b/bin/lock
@@ -5,6 +5,7 @@ IFS=$'\n\t'
 
 LOCK_BG_FILE="/tmp/lock_screen.png"
 
+rm -f "$LOCK_BG_FILE"
 scrot "$LOCK_BG_FILE"
 mogrify -filter Gaussian -resize 50% -define filter:sigma=2.5 -resize 200% "$LOCK_BG_FILE"
 mogrify -font Liberation-Sans -fill white -undercolor '#00000080' -pointsize 30 -gravity South -annotate +0+200 "Screen locked" "$LOCK_BG_FILE"