diff --git a/include/bb2diaspora.php b/include/bb2diaspora.php
index f007417903..75fe1ef35d 100644
--- a/include/bb2diaspora.php
+++ b/include/bb2diaspora.php
@@ -162,6 +162,22 @@ function bb2diaspora($Text,$preserve_nl = false, $fordiaspora = true) {
 	$md = new Markdownify(false, false, false);
 	$Text = $md->parseString($Text);
 
+	// The Markdownify converter converts underscores '_' in URLs to '\_', which
+	// messes up the URL. Manually fix these
+	$count = 1;
+	$pos = bb_find_open_close($Text, '[', ']', $count);
+	while($pos !== false) {
+		$start = substr($Text, 0, $pos['start']);
+		$subject = substr($Text, $pos['start'], $pos['end'] - $pos['start'] + 1);
+		$end = substr($Text, $pos['end'] + 1);
+
+		$subject = str_replace('\_', '_', $subject);
+		$Text = $start . $subject . $end;
+
+		$count++;
+		$pos = bb_find_open_close($Text, '[', ']', $count);
+	}	
+
 	// If the text going into bbcode() has a plain URL in it, i.e.
 	// with no [url] tags around it, it will come out of parseString()
 	// looking like: <http://url.com>, which gets removed by strip_tags().
diff --git a/include/bbcode.php b/include/bbcode.php
index 6f22d19702..c30908e2d4 100644
--- a/include/bbcode.php
+++ b/include/bbcode.php
@@ -47,6 +47,30 @@ function bb_unspacefy_and_trim($st) {
   return $unspacefied;
 }
 
+function bb_find_open_close($s, $open, $close, $occurance = 1) {
+
+	if($occurance < 1)
+		$occurance = 1;
+
+	$start_pos = -1;
+	for($i = 1; $i <= $occurance; $i++) {
+		if( $start_pos !== false)
+			$start_pos = strpos($s, $open, $start_pos + 1);
+	}
+
+	if( $start_pos === false)
+		return false;
+
+	$end_pos = strpos($s, $close, $start_pos);
+
+	if( $end_pos === false)
+		return false;
+
+	$res = array( 'start' => $start_pos, 'end' => $end_pos );
+
+	return $res;
+}
+
 function get_bb_tag_pos($s, $name, $occurance = 1) {
 
 	if($occurance < 1)