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I am doing a simple ionic relaxation for SiC.
my POSCAR has somehow exact positions.
for INCAR:

ISMEAR = -1
SIGMA = 0.001
ISPIN = 1
ENCUT = 420.00 eV
ENAUG = 840.00 eV
NELM = 40
EDIFF = 1E-05
NSW = 10
ADDGRID = .TRUE.
IBRION = 1
ISIF = 3
EDIFFG = -1E-03


but after each ionic step I receive this error:

entering main loop
N E dE d eps ncg rms rms(c)
DAV: 1 0.129828706002E+04 0.12983E+04 -0.39023E+04 17072 0.226E+03
DAV: 2 0.244602139079E+03 -0.10537E+04 -0.99785E+03 11096 0.856E+02
DAV: 3 -0.328803301434E+02 -0.27748E+03 -0.27512E+03 13144 0.249E+02
DAV: 4 -0.586889148843E+02 -0.25809E+02 -0.25784E+02 13584 0.921E+01
DAV: 5 -0.604665811512E+02 -0.17777E+01 -0.17775E+01 14344 0.309E+01 0.157E+01
DAV: 6 -0.533393637525E+02 0.71272E+01 -0.77105E+00 16728 0.191E+01 0.583E+00
DAV: 7 -0.532262676304E+02 0.11310E+00 -0.14832E+00 14320 0.425E+00 0.326E+00
DAV: 8 -0.532189642026E+02 0.73034E-02 -0.11581E-01 15696 0.288E+00 0.554E-01
DAV: 9 -0.532109608027E+02 0.80034E-02 -0.12442E-02 15624 0.127E+00 0.921E-02
DAV: 10 -0.532115058272E+02 -0.54502E-03 -0.22443E-03 15320 0.215E-01 0.847E-02
DAV: 11 -0.532115310038E+02 -0.25177E-04 -0.21751E-04 12624 0.993E-02 0.124E-02
DAV: 12 -0.532115340379E+02 -0.30341E-05 -0.17904E-05 11056 0.301E-02
1 F= -.53211534E+02 E0= -.53211534E+02 d E =-.532115E+02
BRION: g(F)= 0.682E-03 g(S)= 0.200E+03
bond charge predicted
N E dE d eps ncg rms rms(c)
ERROR FEXCP: supplied Exchange-correletion table
is too small, maximal index : 15639


In the XDATCAR I noticed this strange values:(by strange I mean the lattice vectors has become 1/3!!!!)
PBE calculation of SiC primitive c
1
3.093313 0.000000 0.000000
-1.546657 2.678888 0.000000
0.000000 0.000000 10.131661
Si C
4 4
PBE calculation of SiC primitive c
1
1.132618 0.000000 0.000000
-0.566309 0.980876 0.000000
0.000000 0.000000 3.693102
Si C
4 4
Direct configuration= 1
0.00000000 0.00000000 0.00007817
0.33333333 0.66666667 0.24982966
0.66666667 0.33333333 0.50007817
0.33333333 0.66666667 0.74982966
0.00000000 0.00000000 0.18802582
0.33333333 0.66666667 0.43741162
0.66666667 0.33333333 0.68802582
0.33333333 0.66666667 0.93741162

Note that after 10 ionic steps (NSW=10) the system could be far away from thre relaxed structure.

[quote="10) the system could be far away from thre relaxed structure.[/quote"]
Thanks!
Considering the fact that my POSCAR is quite accurate It shouldn't change that much!
Any way, I cannot find any solution for the error!