ValueError: Incorrect value of vasp_type given (None). Please open an issue if you are certain this WAVECAR was generated with the given vasp_type

AMSET
2

This is a limitation of the pymatgen Wavecar class. See this issue for more details and also this thread discussing the same problem. This seems to occur when the WAVECAR file is too large to be read into memory.

Just to confirm, how large is your WAVECAR file?

The best options are:

  1. Ensure that your calculation is using symmetry (ISYM = 2 for GGA calculations and ISYM = 3 for hybrids). This will reduce the number of k-points and dramatically minimise the file size.
  2. Use a smaller k-point mesh; technically, the wavefunction.h5 file does not have to be from the same calculation as the vasprun.xml used to interpolate the band structure.

Other, less ideal options are:

  1. Ensure the number of empty bands is not too large.
  2. Use a smaller ENCUT.

Best,
Alex