diff -up src/sage/libs/mpfr/__init__.pxd.orig src/sage/libs/mpfr/__init__.pxd
--- src/sage/libs/mpfr/__init__.pxd.orig	2018-08-03 05:10:08.000000000 -0600
+++ src/sage/libs/mpfr/__init__.pxd	2018-08-29 10:41:34.027286042 -0600
@@ -96,7 +96,6 @@ cdef extern from "mpfr.h":
     int mpfr_sqrt(mpfr_t rop, mpfr_t op, mpfr_rnd_t rnd)
     int mpfr_sqrt_ui(mpfr_t rop, unsigned long int op, mpfr_rnd_t rnd)
     int mpfr_cbrt(mpfr_t rop, mpfr_t op, mpfr_rnd_t rnd)
-    int mpfr_rootn_ui(mpfr_t rop, mpfr_t op, unsigned long int k, mpfr_rnd_t rnd)
     int mpfr_root(mpfr_t rop, mpfr_t op, unsigned long int k, mpfr_rnd_t rnd)
     int mpfr_pow(mpfr_t rop, mpfr_t op1, mpfr_t op2, mpfr_rnd_t rnd)
     int mpfr_pow_ui(mpfr_t rop, mpfr_t op1, unsigned long int op2, mpfr_rnd_t rnd)
diff -up src/sage/rings/complex_mpc.pyx.orig src/sage/rings/complex_mpc.pyx
--- src/sage/rings/complex_mpc.pyx.orig	2018-08-03 05:10:09.000000000 -0600
+++ src/sage/rings/complex_mpc.pyx	2018-08-29 10:41:34.027286042 -0600
@@ -2225,7 +2225,7 @@ cdef class MPComplexNumber(sage.structur
         cdef RealNumber a,r
         a = self.argument()/n
         r = self.abs()
-        mpfr_rootn_ui(r.value, r.value, n, rrnd)
+        mpfr_root(r.value, r.value, n, rrnd)
 
         cdef MPComplexNumber z
         z = self._new()
diff -up src/sage/rings/complex_number.pyx.orig src/sage/rings/complex_number.pyx
--- src/sage/rings/complex_number.pyx.orig	2018-08-03 05:10:09.000000000 -0600
+++ src/sage/rings/complex_number.pyx	2018-08-29 10:41:34.027286042 -0600
@@ -2276,7 +2276,7 @@ cdef class ComplexNumber(sage.structure.
         rho = abs(self)
         arg = self.argument() / n
         mpfr_init2(r, self._prec)
-        mpfr_rootn_ui(r, rho.value, n, rnd)
+        mpfr_root(r, rho.value, n, rnd)
 
         mpfr_sin_cos(z.__im, z.__re, arg.value, rnd)
         mpfr_mul(z.__re, z.__re, r, rnd)
diff -up src/sage/rings/real_mpfr.pyx.orig src/sage/rings/real_mpfr.pyx
--- src/sage/rings/real_mpfr.pyx.orig	2018-08-03 05:10:09.000000000 -0600
+++ src/sage/rings/real_mpfr.pyx	2018-08-29 10:41:34.028286030 -0600
@@ -5370,7 +5370,7 @@ cdef class RealNumber(sage.structure.ele
         if algorithm == 1:
             x = self._new()
             sig_on()
-            mpfr_rootn_ui(x.value, self.value, n, (<RealField_class>self._parent).rnd)
+            mpfr_root(x.value, self.value, n, (<RealField_class>self._parent).rnd)
             sig_off()
             return x