xxxxxxxxxx
Press Ctrl + H (quick replace).
Click "Use Regular Expressions".
In Find specify "^$\n"
Click "Replace All". All Blank lines will be deleted.
xxxxxxxxxx
^$\n
Replace (Ctrl+H) > Use Regular Expressions > Find `^$\n` > Replace All (Ctrl+Alt+Enter)
xxxxxxxxxx
in find & replace put ^\n with regex enabled in find and rpelace with blank.