This work attempts to understand the effect of initial conditions, i.e., as-milled powder and phase stabilized nearly single phase powder (through annealing), on sintering kinetics of CoCrFeNi high entropy alloy powders. Dilatometric study indicates, axial shrinkage reduced from about 5% to 3% when powder was annealed. Analysis of shrinkage through non-isothermal method shows activation energies of sintering increased significantly for a given model, in annealed powder compared to as-milled powder. Calculated activation energies indicate, in as-milled powder grain boundary diffusion seems to be the dominating mechanism, attributed to the presence of ultrafine grains and a large fraction of grain boundaries. On the other hand, annealing helped to form almost single phase HEA, decrease in defect concentration and reduced grain boundary fraction with increased crystallites; which led to increase in activation energies. Coefficients of thermal expansion have also been studied and it was found to vary with temperature range. (C) 2017 Elsevier B.V. All rights reserved.