diff --git a/src/main/java/baritone/bot/chunk/CachedRegion.java b/src/main/java/baritone/bot/chunk/CachedRegion.java
index a70cfc65..05d6ee9d 100644
--- a/src/main/java/baritone/bot/chunk/CachedRegion.java
+++ b/src/main/java/baritone/bot/chunk/CachedRegion.java
@@ -135,6 +135,7 @@ public final class CachedRegion implements ICachedChunkAccess {
                         }
                     }
                 }
+                out.writeInt(~CACHED_REGION_MAGIC);
             }
             hasUnsavedChanges = false;
         } catch (IOException ignored) {}
@@ -182,6 +183,10 @@ public final class CachedRegion implements ICachedChunkAccess {
                         }
                     }
                 }
+                int fileEndMagic = in.readInt();
+                if (fileEndMagic != ~magic) {
+                    throw new IOException("Bad end of file magic");
+                }
             }
             hasUnsavedChanges = false;
         } catch (IOException ignored) {}