diff --git a/Lib/__init__.py b/Lib/__init__.py
index f122245b..ffd877aa 100644
--- a/Lib/__init__.py
+++ b/Lib/__init__.py
@@ -4,6 +4,7 @@
 
 # Errors
 from .error import CDMSError  # noqa
+from .Cdunif import ReadOnlyKeyError
 from lazy_object_proxy import Proxy
 from . import dataset
 from . import selectors
diff --git a/Lib/dataset.py b/Lib/dataset.py
index 41230d03..c402b44c 100644
--- a/Lib/dataset.py
+++ b/Lib/dataset.py
@@ -2105,7 +2105,13 @@ def createVariableCopy(self, var, id=None, attributes=None, axes=None, extbounds
             if attname not in ["id", "datatype", "parent"]:
                 if isinstance(attval, string_types):
                     attval = str(attval)
-                setattr(newvar, str(attname), attval)
+                try:
+                    setattr(newvar, str(attname), attval)
+                except Cdunif.ReadOnlyKeyError as e:
+                    # Suppress the exception context
+                    err = "Cannot write read-only attribute '{!s}', must be " \
+                        "removed from '{!s}' variable before writing to file".format(e, var.id)
+                    raise CDMSError(err) from None
                 if (attname == "_FillValue") or (attname == "missing_value"):
                     setattr(newvar, "_FillValue", attval)
                     setattr(newvar, "missing_value", attval)
diff --git a/Lib/fvariable.py b/Lib/fvariable.py
index a3625c2d..ddf5c70b 100644
--- a/Lib/fvariable.py
+++ b/Lib/fvariable.py
@@ -157,12 +157,7 @@ def __setattr__(self, name, value):
         if hasattr(self, "parent") and self.parent is None:
             raise CDMSError(FileClosedWrite + self.id)
         if (name not in self.__cdms_internals__) and (value is not None):
-            try:
-                setattr(self._obj_, str(name), value)
-            except Exception:
-                raise CDMSError(
-                    "Setting %s.%s=%s" %
-                    (self.id, name, repr(value)))
+            setattr(self._obj_, str(name), value)
             self.attributes[name] = value
         self.__dict__[name] = value
 
diff --git a/Src/Cdunifmodule.c b/Src/Cdunifmodule.c
index 751feefc..0172042f 100644
--- a/Src/Cdunifmodule.c
+++ b/Src/Cdunifmodule.c
@@ -71,6 +71,7 @@ PyThread_type_lock Cdunif_lock;
 #endif
 
 static PyObject *CdunifError;
+static PyObject *ReadOnlyKeyError;
 
 /* Set error string */
 static void Cdunif_seterror(void) {
@@ -2067,10 +2068,10 @@ static int PyCdunifFile_SetAttribute(PyCdunifFileObject *self, PyObject *nameobj
 	char *name = PyStr_AsString(nameobj);
 	if (check_if_open(self, 1)) {
 		if (strcmp(name, "dimensions") == 0
-		        || strcmp(name, "variables") == 0
+        || strcmp(name, "variables") == 0
 				|| strcmp(name, "dimensioninfo") == 0
 				|| strcmp(name, "__dict__") == 0) {
-			PyErr_SetString(PyExc_TypeError, "object has read-only attributes");
+      PyErr_Format(ReadOnlyKeyError, "%s", name);
 			return -1;
 		}
 		define_mode(self, 1);
@@ -2423,9 +2424,10 @@ static int PyCdunifVariable_SetAttribute(PyCdunifVariableObject *self,
 		PyObject *nameobj, PyObject *value) {
     char *name = PyStr_AsString(nameobj);
 	if (check_if_open(self->file, 1)) {
-		if (strcmp(name, "shape") == 0 || strcmp(name, "dimensions") == 0
+		if (strcmp(name, "shape") == 0 
+        || strcmp(name, "dimensions") == 0
 				|| strcmp(name, "__dict__") == 0) {
-			PyErr_SetString(PyExc_TypeError, "object has read-only attributes");
+      PyErr_Format(ReadOnlyKeyError, "%s", name);
 			return -1;
 		}
 		define_mode(self->file, 1);
@@ -3456,9 +3458,11 @@ MODULE_INIT_FUNC (Cdunif) {
        PyCapsule_New((void *) PyCdunif_API, "_C_API", NULL));
 
 
-    CdunifError = PyStr_FromString("CdunifError");
+  CdunifError = PyStr_FromString("CdunifError");
+  ReadOnlyKeyError = PyErr_NewException("Cdunif.ReadOnlyKeyError", NULL, NULL);
 
 	PyDict_SetItemString(d, "CdunifError", CdunifError);
+  PyDict_SetItemString(d, "ReadOnlyKeyError", ReadOnlyKeyError);
 
 	/* Check for errors */
 	if (PyErr_Occurred())
diff --git a/tests/test_dataset_io.py b/tests/test_dataset_io.py
index d3ff7ffd..e23bbecf 100644
--- a/tests/test_dataset_io.py
+++ b/tests/test_dataset_io.py
@@ -3,6 +3,9 @@
 import string
 import os
 import sys
+import cdat_info
+import subprocess
+import shutil
 
 cdms2.setNetcdfUseParallelFlag(0)
 
@@ -21,6 +24,34 @@ def setUp(self):
     def testFileAttributes(self):
         self.assertEqual(self.file.id, "test")
 
+    def testWriteReadOnlyAttribute(self):
+        out = self.getTempFile("read_only.nc", "w")
+        out.write(self.u)
+        out.close()
+
+        temp = self.getTempFile("read_only.nc", "a")
+
+        with self.assertRaises(cdms2.ReadOnlyKeyError):
+            setattr(temp, "dimensions", "test")
+
+        with self.assertRaises(cdms2.ReadOnlyKeyError):
+            setattr(temp["u"], "dimensions", "test")
+
+    def testWriteThroughReadOnlyAtttribute(self):
+        iname = os.path.join(cdat_info.get_sampledata_path(), "clt.nc")
+        oname = os.path.join(os.getcwd(), "clt-modded.nc")
+
+        shutil.copyfile(iname, oname)
+
+        subprocess.run(["ncatted", "-a", "dimensions,clt,c,c,'lat lon'", oname])
+
+        ifile = cdms2.open(oname)
+        data = ifile("clt")
+        ifile.close()
+
+        with cdms2.open(oname, "w") as ofile, self.assertRaises(cdms2.CDMSError):
+            ofile.write(data)
+
     def testScalarSlice(self):
         u = self.u
         scalar = u[0,0,0]