diff --git a/JFile.cpp b/JFile.cpp
index 4cfac59..ed64f43 100644
--- a/JFile.cpp
+++ b/JFile.cpp
@@ -4,7 +4,20 @@
 
 namespace coreutils {
 
-   JFile::JFile(ZString filename) : MFile(filename) {}
+   // MFile and JString share a single virtual MString base (the diamond:
+   // both "MFile : virtual public MString" and "JString : virtual public
+   // MString"), and a virtual base is initialized only by the *most
+   // derived* class's constructor - so JString's own "{}" default
+   // initializer never runs here. Left alone, a JFile backed by a new or
+   // empty file starts as a raw empty string instead of a valid empty JSON
+   // object, and every subsequent locate()/set() call silently misbehaves
+   // (no leading "{" for ifNext("{") to match, so writes end up inserted
+   // at offset 0 with no braces or separators at all). Detect that case
+   // here and seed valid JSON explicitly.
+   JFile::JFile(ZString filename) : MFile(filename) {
+      if(getLength() == 0)
+	*this << "{}";
+   }
       
    
 }
diff --git a/MString.cpp b/MString.cpp
index 360f91f..303a590 100644
--- a/MString.cpp
+++ b/MString.cpp
@@ -48,13 +48,13 @@ namespace coreutils {
 
    MString::MString(const ZString &zstring) {
       setSize(zstring.getLength());
-      memcpy(data, zstring.getData(), zstring.getLength());
-      cursor = data;      
-   }   
+      memcpy(data, zstring.getCursor(), zstring.getLength());
+      cursor = data;
+   }
 
    MString::MString(ZString &zstring) {
       setSize(zstring.getLength());
-      memcpy(data, zstring.getData(), zstring.getLength());
+      memcpy(data, zstring.getCursor(), zstring.getLength());
       cursor = data;
    }
   
@@ -66,7 +66,7 @@ namespace coreutils {
    
    MString::MString(MString &mstring) {
       setSize(mstring.getLength());
-      memcpy(data, mstring.getData(), mstring.getLength());
+      memcpy(data, mstring.getCursor(), mstring.getLength());
       cursor = data;
    }
    
@@ -106,7 +106,7 @@ namespace coreutils {
    
    MString &MString::operator=(coreutils::MString value) {
       setSize(value.getLength());
-      memcpy(data, value.getData(), value.getLength());
+      memcpy(data, value.getCursor(), value.getLength());
       length = value.getLength();
       onChange();
       return *this;
@@ -114,7 +114,7 @@ namespace coreutils {
 
    MString &MString::operator=(coreutils::ZString value) {
       setSize(value.getLength());
-      memcpy(data, value.getData(), value.getLength());
+      memcpy(data, value.getCursor(), value.getLength());
       length = value.getLength();
       onChange();
       return *this;
@@ -195,7 +195,7 @@ namespace coreutils {
       int temp = length;
       int len = length + zstring.getLength();
       setSize(len);
-      memcpy(data + temp, zstring.getData(), zstring.getLength());
+      memcpy(data + temp, zstring.getCursor(), zstring.getLength());
       onChange();
       return *this;
    }
@@ -240,7 +240,7 @@ namespace coreutils {
       setSize(length + value.getLength());
       for (int ix = length; ix >= offset; ix--)
 	getData()[ix] = getData()[ix - value.getLength()];
-      std::memcpy(data + offset, value.getData(), value.getLength());
+      std::memcpy(data + offset, value.getCursor(), value.getLength());
       onChange();
    }
    
@@ -285,7 +285,7 @@ namespace coreutils {
    MString &MString::write(ZString value) {
       int len = length;
       setSize(length + value.getLength());
-      memcpy(data + len, value.getData(), value.getLength());
+      memcpy(data + len, value.getCursor(), value.getLength());
       onChange();
       return *this;
    }