Hi Aman,
It might be too late, but in case: to convert .hic files to .cool, I used the `hicConvertFormat` function from HiCExplorer as such:
hicConvertFormat -m matrix.hic \
--inputFormat hic \
--outputFormat cool \
-o matrix.cool \
--resolutions
I don't know how this issue that you cited arose, but I had no issue, so it might have been fixed.
Hope this can help,
Best wishes,
Alice