This is WhatsHap 2.8 running under Python 3.9.23
[W::hts_idx_load3] The index file is older than the data file: FFPE_HD789_01_p2_gDNA_01_A23MHWWLT4_1.recalibrated.bam.bai
[W::hts_idx_load3] The index file is older than the data file: FFPE_HD789_01_p2_gDNA_01_A23MHWWLT4_1.recalibrated.bam.bai
[E::idx_find_and_load] Could not retrieve index file for 'input_filtered.vcf.gz'
[E::idx_find_and_load] Could not retrieve index file for 'input_filtered.vcf.gz'
[E::idx_find_and_load] Could not retrieve index file for 'input_filtered.vcf.gz'
Working on 2 samples from 2 families

# Working on contig chr6_GL000251v2_alt in individual FFPE_HD789_01_p2_gDNA_01_A23MHWWLT4_1
Found 2 usable heterozygous variants (0 skipped due to missing genotypes)
[W::hts_idx_load3] The index file is older than the data file: FFPE_HD789_01_p2_gDNA_01_A23MHWWLT4_1.recalibrated.bam.bai
Number of supplementary alignments: 0
Number of non-singleton groups: 0
Skipped 0 groups
Found 1 reads covering 2 variants
Kept 1 reads that cover at least two variants each
Selected 1 most phase-informative reads covering 2 variants
Best-case phasing would result in 1 non-singleton phased block (0 singletons). 
Phasing 1 sample by solving the MEC problem ...
Largest block contains 2 variants (100.0% of accessible variants) between position 3938915 and 3938917

# Working on contig chr6_GL000251v2_alt in individual reference-NA12878
Found 0 usable heterozygous variants (0 skipped due to missing genotypes)
WARNING: Sample 'reference-NA12878' not found in any BAM/CRAM file.
Found 0 reads covering 0 variants
Kept 0 reads that cover at least two variants each
Selected 0 most phase-informative reads covering 0 variants
Best-case phasing would result in 0 non-singleton phased blocks (0 singletons). 
Phasing 1 sample by solving the MEC problem ...
No. of phased blocks: 0

# Resource usage
Maximum memory usage: 0.098 GB
Time spent reading BAM/CRAM:                    1.3 s
Time spent parsing VCF:                         0.0 s
Time spent selecting reads:                     0.0 s
Time spent phasing:                             0.0 s
Time spent writing VCF:                         0.0 s
Time spent finding components:                  0.0 s
Time spent on rest:                             0.1 s
Total elapsed time:                             1.5 s