diff --git a/LIBTOOLS/tools/lfi2cdf/src/mode_util.f90 b/LIBTOOLS/tools/lfi2cdf/src/mode_util.f90
index 7310461099d350a5ab9d4e2207dbbb1b2bcf3dc1..2fcdf133ee1ce57ee3ccdfdd8ae55f04d2f89747 100644
--- a/LIBTOOLS/tools/lfi2cdf/src/mode_util.f90
+++ b/LIBTOOLS/tools/lfi2cdf/src/mode_util.f90
@@ -1354,7 +1354,7 @@ END DO
       outfiles%files(idx)%var_id = ji
 
       IF (options(OPTCDF4)%set) THEN
-        filename = trim(houtfile)//'.'//trim(tpreclist(ji)%name)//'.nc4'
+        filename = trim(houtfile)//'.'//trim(tpreclist(ji)%name)//'.nc'
         status = NF90_CREATE(trim(filename), IOR(NF90_CLOBBER,NF90_NETCDF4), outfiles%files(idx)%lun_id)
       ELSE
         filename = trim(houtfile)//'.'//trim(tpreclist(ji)%name)//'.nc'
diff --git a/src/LIB/SURCOUCHE/src/mode_fm.f90 b/src/LIB/SURCOUCHE/src/mode_fm.f90
index d549bcc0e3694c3897ef6b96c7f1360f264bc705..dc7d1416bad83cf58c7e2b02052aa1988d6943ca 100644
--- a/src/LIB/SURCOUCHE/src/mode_fm.f90
+++ b/src/LIB/SURCOUCHE/src/mode_fm.f90
@@ -257,26 +257,26 @@ IF (ISP == TZFDLFI%OWNER) THEN
      IF (HACTION == 'READ' .AND. .NOT. LLFIREAD) THEN
         !! Open NetCDF File for reading
         TZFDLFI%CDF => NEWIOCDF()
-        INCERR = NF90_OPEN(ADJUSTL(TRIM(HFILEM))//".nc4", NF90_NOWRITE, TZFDLFI%CDF%NCID)
+        INCERR = NF90_OPEN(ADJUSTL(TRIM(HFILEM))//".nc", NF90_NOWRITE, TZFDLFI%CDF%NCID)
         IF (INCERR /= NF90_NOERR) THEN
            !PRINT *, 'FMOPEN_ll, NF90_OPEN error : ', NF90_STRERROR(INCERR)
-           PRINT *, 'Error in opening (FMOPEN_ll/NF90_OPEN) ', TRIM(HFILEM)//'.nc4', ' : ', NF90_STRERROR(INCERR)
+           PRINT *, 'Error in opening (FMOPEN_ll/NF90_OPEN) ', TRIM(HFILEM)//'.nc', ' : ', NF90_STRERROR(INCERR)
            STOP
         END IF
-        PRINT *, 'NF90_OPEN: ', TRIM(HFILEM)//'.nc4'
+        PRINT *, 'NF90_OPEN: ', TRIM(HFILEM)//'.nc'
      END IF
      
      IF (HACTION == 'WRITE') THEN
         ! HACTION == 'WRITE'
         TZFDLFI%CDF => NEWIOCDF()
-        INCERR = NF90_CREATE(ADJUSTL(TRIM(HFILEM))//".nc4", &
+        INCERR = NF90_CREATE(ADJUSTL(TRIM(HFILEM))//".nc", &
              &IOR(NF90_CLOBBER,NF90_NETCDF4), TZFDLFI%CDF%NCID)
         IF (INCERR /= NF90_NOERR) THEN
            !PRINT *, 'FMOPEN_ll, NF90_CREATE error : ', NF90_STRERROR(INCERR)
-           PRINT *, 'Error in opening (FMOPEN_ll/NF90_CREATE) ', TRIM(HFILEM)//'.nc4', ' : ', NF90_STRERROR(INCERR)
+           PRINT *, 'Error in opening (FMOPEN_ll/NF90_CREATE) ', TRIM(HFILEM)//'.nc', ' : ', NF90_STRERROR(INCERR)
            STOP
         END IF
-        PRINT *, 'NF90_CREATE: ', TRIM(HFILEM)//'.nc4'
+        PRINT *, 'NF90_CREATE: ', TRIM(HFILEM)//'.nc'
      END IF
   END IF
 #endif
diff --git a/src/LIB/SURCOUCHE/src/mode_io.f90 b/src/LIB/SURCOUCHE/src/mode_io.f90
index 105c16b0d5d90c59fe2974388707043b54a295f8..3667364c5032b34c3122562569663064cccf0d34 100644
--- a/src/LIB/SURCOUCHE/src/mode_io.f90
+++ b/src/LIB/SURCOUCHE/src/mode_io.f90
@@ -664,29 +664,29 @@ CONTAINS
                    IF (YACTION == 'READ' .AND. .NOT. LLFIREAD) THEN
                       ! Open NetCDF File for reading
                       TZFD_IOZ%CDF => NEWIOCDF()
-                      IOSCDF = NF90_OPEN(TRIM(FILE)//cfile//".nc4", NF90_NOWRITE, TZFD_IOZ%CDF%NCID)
+                      IOSCDF = NF90_OPEN(TRIM(FILE)//cfile//".nc", NF90_NOWRITE, TZFD_IOZ%CDF%NCID)
                       IF (IOSCDF /= NF90_NOERR) THEN
-   PRINT *, 'Error in opening (NF90_OPEN) ', TRIM(FILE)//cfile//'.nc4', ' : ', NF90_STRERROR(IOSCDF)
+   PRINT *, 'Error in opening (NF90_OPEN) ', TRIM(FILE)//cfile//'.nc', ' : ', NF90_STRERROR(IOSCDF)
                          STOP
                       ELSE
                          IOS = 0
                       END IF
-                      PRINT *, 'NF90_OPEN(IO_ZSPLIT): ',TRIM(FILE)//cfile//'.nc4'
+                      PRINT *, 'NF90_OPEN(IO_ZSPLIT): ',TRIM(FILE)//cfile//'.nc'
                    END IF
                    
                    IF (YACTION == 'WRITE') THEN
                       ! YACTION == 'WRITE'
                       ! Create NetCDF File for writing
                       TZFD_IOZ%CDF => NEWIOCDF()
-                      IOSCDF = NF90_CREATE(TRIM(FILE)//cfile//".nc4", &
+                      IOSCDF = NF90_CREATE(TRIM(FILE)//cfile//".nc", &
                            &IOR(NF90_CLOBBER,NF90_NETCDF4), TZFD_IOZ%CDF%NCID)
                       IF (IOSCDF /= NF90_NOERR) THEN
-                         PRINT *, 'Error in opening (NF90_CREATE) ', TRIM(FILE)//cfile//'.nc4', ' : ', NF90_STRERROR(IOSCDF)
+                         PRINT *, 'Error in opening (NF90_CREATE) ', TRIM(FILE)//cfile//'.nc', ' : ', NF90_STRERROR(IOSCDF)
                          STOP
                       ELSE
                          IOS = 0
                       END IF
-                      PRINT *, 'NF90_CREATE(IO_ZSPLIT): ',TRIM(FILE)//cfile//'.nc4'
+                      PRINT *, 'NF90_CREATE(IO_ZSPLIT): ',TRIM(FILE)//cfile//'.nc'
                    END IF
                 END IF
 #endif