diff --git a/lib/AbstractException.php b/lib/AbstractException.php
index 1e3a2dd..0165d46 100644
--- a/lib/AbstractException.php
+++ b/lib/AbstractException.php
@@ -94,6 +94,7 @@ abstract class AbstractException extends \Exception {
         "ImportExport/Exception.invalidSemantics"     => 10612,
         "ImportExport/Exception.invalidFolderName"    => 10613,
         "ImportExport/Exception.invalidFolderCopy"    => 10614,
+        "ImportExport/Exception.invalidTagName"       => 10615,
     ];
 
     public function __construct(string $msgID = "", $vars = null, \Throwable $e = null) {
diff --git a/lib/ImportExport/AbstractImportExport.php b/lib/ImportExport/AbstractImportExport.php
index 3a23443..66cc9b2 100644
--- a/lib/ImportExport/AbstractImportExport.php
+++ b/lib/ImportExport/AbstractImportExport.php
@@ -85,8 +85,8 @@ abstract class AbstractImportExport {
                 // compile the set of used tags, if this is a new feed or we're doing a full replacement
                 foreach ($f['tags'] as $t) {
                     if (!strlen(trim($t))) {
-                        // ignore any blank tags
-                        continue;
+                        // fail if we have any blank tags
+                        throw new Exception("invalidTagName");
                     }
                     if (!isset($tagMap[$t])) {
                         // populate the tag map
diff --git a/lib/ImportExport/OPML.php b/lib/ImportExport/OPML.php
index aa311f8..30a3cc5 100644
--- a/lib/ImportExport/OPML.php
+++ b/lib/ImportExport/OPML.php
@@ -61,6 +61,10 @@ class OPML extends AbstractImportExport {
                         $categories = array_map(function($v) {
                             return trim(preg_replace("/\s+/", " ", $v));
                         }, explode(",", $categories));
+                        // filter out any blank categories
+                        $categories = array_filter($categories, function($v) {
+                            return strlen($v);
+                        });
                     } else {
                         $categories = [];
                     }
diff --git a/locale/en.php b/locale/en.php
index 19fc724..e095db8 100644
--- a/locale/en.php
+++ b/locale/en.php
@@ -163,4 +163,5 @@ return [
     'Exception.JKingWeb/Arsse/ImportExport/Exception.invalidSemantics'     => 'Input data is not valid {type} data',
     'Exception.JKingWeb/Arsse/ImportExport/Exception.invalidFolderName'    => 'Input data contains an invalid folder name',
     'Exception.JKingWeb/Arsse/ImportExport/Exception.invalidFolderCopy'    => 'Input data contains multiple folders of the same name under the same parent',
+    'Exception.JKingWeb/Arsse/ImportExport/Exception.invalidTagName'       => 'Input data contains an invalid tag name',
 ];
diff --git a/tests/cases/ImportExport/TestOPML.php b/tests/cases/ImportExport/TestOPML.php
index e4ef7b4..503211c 100644
--- a/tests/cases/ImportExport/TestOPML.php
+++ b/tests/cases/ImportExport/TestOPML.php
@@ -135,7 +135,7 @@ OPML_EXPORT_SERIALIZATION;
                 ['url' => "http://example.com/3", 'title' => "",       'folder' => 0, 'tags' => []],
                 ['url' => "http://example.com/4", 'title' => "",       'folder' => 0, 'tags' => []],
                 ['url' => "",                     'title' => "",       'folder' => 0, 'tags' => ["whee"]],
-                ['url' => "",                     'title' => "",       'folder' => 0, 'tags' => ["whee", "whoo", ""]],
+                ['url' => "",                     'title' => "",       'folder' => 0, 'tags' => ["whee", "whoo"]],
             ], []]],
             ["FoldersOnly.opml", true, [[], []]],
             ["FoldersOnly.opml", false, [[], [1 =>