diff --git a/app/src/main/kotlin/net/h34t/filemure/Types.kt b/app/src/main/kotlin/net/h34t/filemure/Types.kt
index 5082963..59edcd5 100644
--- a/app/src/main/kotlin/net/h34t/filemure/Types.kt
+++ b/app/src/main/kotlin/net/h34t/filemure/Types.kt
@@ -45,7 +45,9 @@ value class Tag private constructor(val value: String) {
         private val splitter = Regex("\\s+")
         fun of(value: String): Tag =
             value.trim().let { v ->
-                require(v.matches(validator))
+                require(v.matches(validator)) {
+                    "\"$value\" isn't a valid tag"
+                }
                 Tag(v.lowercase())
             }
 
diff --git a/app/src/main/kotlin/net/h34t/filemure/Util.kt b/app/src/main/kotlin/net/h34t/filemure/Util.kt
index 7676738..9999b13 100644
--- a/app/src/main/kotlin/net/h34t/filemure/Util.kt
+++ b/app/src/main/kotlin/net/h34t/filemure/Util.kt
@@ -52,11 +52,16 @@ private val tagSplitRegex = Regex("\\s+")
 
 object TagAdapter {
     fun parse(ser: String?): List<Tag> {
-        return ser?.trim()?.let { if (it.isNotBlank()) it.split(tagSplitRegex).map { Tag.of(it) } else emptyList() }
+        return ser?.trim()?.let {
+            if (it.isNotBlank()) it
+                .split(tagSplitRegex)
+                .filter { it.isNotBlank() }
+                .map { Tag.of(it) } else emptyList()
+        }
             ?: emptyList()
     }
 
-    fun List<Tag>.serialize() = if (this.isEmpty()) "" else this.joinToString(",") { it.value }
+    fun List<Tag>.serialize() = if (this.isEmpty()) "" else this.joinToString(" ") { it.value }
 }
 
 fun List<Document>.grouped(): Map<Int, Map<Month, List<Document>>> =