foreach (@arraydirectory){
        my $cleansource = $source; $cleansource .= "\\"; $cleansource 
+.= $_;
        $sourceResult = dir_size($cleansource, $sourceDirInfo,);
        $sbyte += $sourceDirInfo->{DirSize}; 
        $sourceSize = best_convert($sourceSizeUnit, $sourceDirInfo->{H
+ighSize}, $sourceDirInfo->{LowSize},);
        my $s = $sourceSize;
        $s .= $sourceSizeUnit;
        $table->add($_);
        $table->itemCreate($_, 0, -text => $_);
        $table->itemCreate($_, 1, -text => $s);
    }#foreach
[download]

For clarification, what kind of "hurtle" are you seeing? Is it messing up when it tries to itemCreate() because of the duplicate name? Is it reporting a wrong size? Are we talking duplicate full paths or just duplicate bottom-level folder names (c:/foo/bar/baz and c:/windows/baz, for instance)?

While I'm here, you could make the code a little more concise:

# Line 2
my $cleansource = "$course\\$_";
# or: my $cleansource = $course . "\\" . $_;

# Lines 6/7
my $s = "$sourceSize$sourceSizeUnit";
# or: my $s = $sourceSize . $sourceSizeUnit
[download]

Using x= (with x being some operator) is only more efficient when working with one additional value. Which looks better to you:

$x = $a; $x += $b; $x += $c; $x += $d;

$x = $a + $b + $c + $d;
[download]

The latter involves less typing, looks much clearer, and is likely more efficient. Sorry to be nitpicky. I'm often anal about grammar and all things related (both in code and in language)

[id://wink] waits for someone to find a grammar mistake in this reply (no, I didn't place one intentionally for anyone to find, but I likely made one). ;)