diff --git a/nise-backend/src/main/kotlin/com/nisemoe/nise/service/CompressJudgements.kt b/nise-backend/src/main/kotlin/com/nisemoe/nise/service/CompressJudgements.kt
index a6dac70..24a1597 100644
--- a/nise-backend/src/main/kotlin/com/nisemoe/nise/service/CompressJudgements.kt
+++ b/nise-backend/src/main/kotlin/com/nisemoe/nise/service/CompressJudgements.kt
@@ -71,7 +71,8 @@ class CompressJudgements {
     }
 
     fun deserialize(compressedData: ByteArray): List<CircleguardService.ScoreJudgement> {
-        val data = Decoder.decompress(compressedData).decompressedData
+        val data = Decoder.decompress(compressedData).decompressedData ?: return emptyList()
+
         val buffer = ByteBuffer.wrap(data)
         val judgements = mutableListOf<CircleguardService.ScoreJudgement>()
         var lastTime = 0.0