diff --git a/brouter-mapaccess/src/main/java/btools/mapaccess/PhysicalFile.java b/brouter-mapaccess/src/main/java/btools/mapaccess/PhysicalFile.java
index 921bd31..6b043bd 100644
--- a/brouter-mapaccess/src/main/java/btools/mapaccess/PhysicalFile.java
+++ b/brouter-mapaccess/src/main/java/btools/mapaccess/PhysicalFile.java
@@ -37,6 +37,27 @@ final public class PhysicalFile {
     }
   }
 
+  public static int checkVersionIntegrity(File f) {
+    int version = -1;
+    RandomAccessFile raf = null;
+    try {
+      byte[] iobuffer = new byte[200];
+      raf = new RandomAccessFile(f, "r");
+      raf.readFully(iobuffer, 0, 200);
+      ByteDataReader dis = new ByteDataReader(iobuffer);
+      long lv = dis.readLong();
+      version = (int) (lv >> 48);
+    } catch (IOException e) {
+    } finally {
+      try {
+        if (raf != null) raf.close();
+      } catch (IOException e) {
+        throw new RuntimeException(e);
+      }
+    }
+    return version;
+  }
+
   /**
    * Checks the integrity of the file using the build-in checksums
    *
@@ -81,7 +102,7 @@ final public class PhysicalFile {
       short readVersion = (short) (lv >> 48);
       if (i == 0 && lookupVersion != -1 && readVersion != lookupVersion) {
         throw new IOException("lookup version mismatch (old rd5?) lookups.dat="
-          + lookupVersion + " " + f.getAbsolutePath() + "=" + readVersion);
+          + lookupVersion + " " + f.getName() + "=" + readVersion);
       }
       fileIndex[i] = lv & 0xffffffffffffL;
     }