diff --git a/ArcFormats/MAGES/ArcLoveOnce.cs b/ArcFormats/MAGES/ArcLoveOnce.cs
index 1fc51465..3463f8e0 100644
--- a/ArcFormats/MAGES/ArcLoveOnce.cs
+++ b/ArcFormats/MAGES/ArcLoveOnce.cs
@@ -22,12 +22,14 @@ namespace GameRes.Formats.MAGES
             {
                 string filepath = Path.GetDirectoryName(filedata.Name);
                 filepath = Path.Combine(filepath, "list.bin");
+                if (! File.Exists(filepath)) return null;
                 filelist = new ArcView(filepath);
             }
             else if (filedata.Name.EndsWith("list.bin"))
             {
                 string filepath = Path.GetDirectoryName(filedata.Name);
                 filepath = Path.Combine(filepath, "data.bin");
+                if (!File.Exists(filepath)) return null;
                 filelist = new ArcView(filepath);
                 return TryOpen(filelist);
             }
diff --git a/ArcFormats/NipponIchi/ArcCASN.cs b/ArcFormats/NipponIchi/ArcCASN.cs
index fe2eb2c7..d76a7db3 100644
--- a/ArcFormats/NipponIchi/ArcCASN.cs
+++ b/ArcFormats/NipponIchi/ArcCASN.cs
@@ -16,6 +16,8 @@ namespace GameRes.Formats.NipponIchi
         public override ArcFile TryOpen(ArcView file)
         {
             int count = Binary.BigEndian(file.View.ReadUInt16(6));
+            if (!IsSaneCount(count))
+                return null;
             long index_offset = count * 10 + 30; //actually count*10 + 28, ignored two bytes of 000C or 000B
             var dir = new List<Entry>(count);
             for (int i = 0; i < count; ++i)