I have a problem with liftOver. I have 300,000 snps to convert from hg18 to hg19,so I use liftOver. I download it in my own computer and run it.I also download the chain which is hg18 to hg19. I found that it can handle most of snps, but will fail about 10,000 snps. I search the failed snps in NCBI, and found they are actually in NCBI, and have position of hg18 and hg19. How can I do do convert the remainder snps? I want to handle them in batches.