diff --git a/src/clib/pio_internal.h b/src/clib/pio_internal.h
index 25e67e89594..0379929e6be 100644
--- a/src/clib/pio_internal.h
+++ b/src/clib/pio_internal.h
@@ -186,7 +186,7 @@ extern "C" {
     int get_var_desc(int varid, var_desc_t **varlist, var_desc_t **var_desc);
     int delete_var_desc(int varid, var_desc_t **varlist);
 
-    /* Create a file (internal function). */
+    /* Create a file. */
     int PIOc_createfile_int(int iosysid, int *ncidp, int *iotype, const char *filename,
                             int mode, int use_ext_ncid);
 
diff --git a/src/clib/pioc_support.c b/src/clib/pioc_support.c
index 21f2c83db13..040e1659f12 100644
--- a/src/clib/pioc_support.c
+++ b/src/clib/pioc_support.c
@@ -1930,7 +1930,8 @@ PIOc_writemap_from_f90(const char *file, int ndims, const int *gdims,
  * @param iosysid A defined pio system ID, obtained from
  * PIOc_Init_Intracomm() or PIOc_InitAsync().
  * @param ncidp A pointer that gets the ncid of the newly created
- * file.
+ * file. For NetCDF integration, this contains the ncid assigned by
+ * the netCDF layer, which is used instead of a PIO-generated ncid.
  * @param iotype A pointer to a pio output format. Must be one of
  * PIO_IOTYPE_PNETCDF, PIO_IOTYPE_NETCDF, PIO_IOTYPE_NETCDF4C, or
  * PIO_IOTYPE_NETCDF4P.
diff --git a/src/ncint/ncintdispatch.c b/src/ncint/ncintdispatch.c
index bdbcd52fdc4..cf0c3e5116d 100644
--- a/src/ncint/ncintdispatch.c
+++ b/src/ncint/ncintdispatch.c
@@ -162,7 +162,8 @@ PIO_NCINT_finalize(void)
  * @param parameters pointer to struct holding extra data (e.g. for
  * parallel I/O) layer. Ignored if NULL.
  * @param dispatch Pointer to the dispatch table for this file.
- * @param nc_file Pointer to an already-existing instance of NC.
+ * @param ncid The ncid assigned to this file by netCDF (aka
+ * ext_ncid).
  *
  * @return ::NC_NOERR No error, or error code.
  * @author Ed Hartnett
@@ -170,8 +171,9 @@ PIO_NCINT_finalize(void)
 int
 PIO_NCINT_create(const char *path, int cmode, size_t initialsz, int basepe,
                  size_t *chunksizehintp, void *parameters,
-                 const NC_Dispatch *dispatch, NC *nc_file)
+                 const NC_Dispatch *dispatch, int ncid)
 {
+    NC *nc;
     int iotype;
     iosystem_desc_t *ios;  /* Pointer to io system information. */
     int ret;
@@ -189,14 +191,17 @@ PIO_NCINT_create(const char *path, int cmode, size_t initialsz, int basepe,
     if ((ret = find_iotype_from_omode(cmode, &iotype)))
         return pio_err(ios, NULL, ret, __FILE__, __LINE__);
 
+    /* Find NC pointer for this file. */
+    if ((ret = NC_check_id(ncid, &nc)))
+        return ret;
+
     /* Add necessary structs to hold netcdf-4 file data. */
-    if ((ret = nc4_nc4f_list_add(nc_file, path, cmode)))
+    if ((ret = nc4_nc4f_list_add(nc, path, cmode)))
         return ret;
 
-    /* Open the file with PIO. Tell openfile_retry to accept the
-     * externally assigned ncid. */
-    if ((ret = PIOc_createfile_int(diosysid,  &nc_file->ext_ncid, &iotype,
-                                   path, cmode, 1)))
+    /* Create the file with PIO. The final parameter tests
+     * createfile_int to accept the externally assigned ncid. */
+    if ((ret = PIOc_createfile_int(diosysid, &ncid, &iotype, path, cmode, 1)))
         return ret;
 
     return PIO_NOERR;
@@ -212,8 +217,7 @@ PIO_NCINT_create(const char *path, int cmode, size_t initialsz, int basepe,
  * @param parameters pointer to struct holding extra data (e.g. for
  * parallel I/O) layer. Ignored if NULL. Ignored by this function.
  * @param dispatch Pointer to the dispatch table for this file.
- * @param nc_file Pointer to an instance of NC. The ncid has already
- * been assigned, and is in nc_file->ext_ncid.
+ * @param ncid
  *
  * @return ::NC_NOERR No error.
  * @return ::NC_EINVAL Invalid input.
@@ -223,8 +227,9 @@ PIO_NCINT_create(const char *path, int cmode, size_t initialsz, int basepe,
  */
 int
 PIO_NCINT_open(const char *path, int mode, int basepe, size_t *chunksizehintp,
-               void *parameters, const NC_Dispatch *dispatch, NC *nc_file)
+               void *parameters, const NC_Dispatch *dispatch, int ncid)
 {
+    NC *nc;
     int iotype;
     iosystem_desc_t *ios;  /* Pointer to io system information. */
     int ret;
@@ -242,14 +247,17 @@ PIO_NCINT_open(const char *path, int mode, int basepe, size_t *chunksizehintp,
     if ((ret = find_iotype_from_omode(mode, &iotype)))
         return pio_err(ios, NULL, ret, __FILE__, __LINE__);
 
+    /* Find NC pointer for this file. */
+    if ((ret = NC_check_id(ncid, &nc)))
+        return ret;
+
     /* Add necessary structs to hold netcdf-4 file data. */
-    if ((ret = nc4_nc4f_list_add(nc_file, path, mode)))
+    if ((ret = nc4_nc4f_list_add(nc, path, mode)))
         return ret;
 
     /* Open the file with PIO. Tell openfile_retry to accept the
      * externally assigned ncid. */
-    if ((ret = PIOc_openfile_retry(diosysid, &nc_file->ext_ncid, &iotype,
-                                   path, mode, 0, 1)))
+    if ((ret = PIOc_openfile_retry(diosysid, &ncid, &iotype, path, mode, 0, 1)))
         return ret;
 
     return NC_NOERR;
diff --git a/src/ncint/ncintdispatch.h b/src/ncint/ncintdispatch.h
index fad328c54e4..8afec9f8a9e 100644
--- a/src/ncint/ncintdispatch.h
+++ b/src/ncint/ncintdispatch.h
@@ -22,12 +22,12 @@ extern "C" {
 
     extern int
     PIO_NCINT_open(const char *path, int mode, int basepe, size_t *chunksizehintp,
-                  void *parameters, const NC_Dispatch *, NC *);
+                  void *parameters, const NC_Dispatch *, int);
 
     extern int
     PIO_NCINT_create(const char* path, int cmode, size_t initialsz, int basepe,
                     size_t *chunksizehintp, void *parameters,
-                    const NC_Dispatch *dispatch, NC *nc_file);
+                    const NC_Dispatch *dispatch, int);
 
     extern int
     PIO_NCINT_def_var(int ncid, const char *name, nc_type xtype, int ndims,
diff --git a/tests/cunit/test_darray.c b/tests/cunit/test_darray.c
index 3c5317ff73b..5b8f32eda85 100644
--- a/tests/cunit/test_darray.c
+++ b/tests/cunit/test_darray.c
@@ -106,7 +106,8 @@ int test_darray(int iosysid, int ioid, int num_flavors, int *flavor, int my_rank
 
     /* Use PIO to create the example file in each of the four
      * available ways. */
-    for (int fmt = 0; fmt < num_flavors; fmt++)
+    /* for (int fmt = 0; fmt < num_flavors; fmt++) */
+    for (int fmt = 3; fmt < 4; fmt++)
     {
 
         /* Add a couple of extra tests for the
@@ -384,7 +385,7 @@ int main(int argc, char **argv)
 
     /* Initialize test. */
     if ((ret = pio_test_init2(argc, argv, &my_rank, &ntasks, MIN_NTASKS,
-                              MIN_NTASKS, -1, &test_comm)))
+                              MIN_NTASKS, 3, &test_comm)))
         ERR(ERR_INIT);
 
     if ((ret = PIOc_set_iosystem_error_handling(PIO_DEFAULT, PIO_RETURN_ERROR, NULL)))
diff --git a/tests/cunit/test_iosystem2_simple.c b/tests/cunit/test_iosystem2_simple.c
index 863d94faf6e..aaf2ddf4d44 100644
--- a/tests/cunit/test_iosystem2_simple.c
+++ b/tests/cunit/test_iosystem2_simple.c
@@ -45,7 +45,7 @@ int main(int argc, char **argv)
 
     /* Initialize test. */
     if ((ret = pio_test_init2(argc, argv, &my_rank, &ntasks, TARGET_NTASKS, TARGET_NTASKS,
-                              -1, &test_comm)))
+                              3, &test_comm)))
         ERR(ERR_INIT);
 
     /* Test code runs on TARGET_NTASKS tasks. The left over tasks do