Many users cannot access Outlook due to corrupted profiles or removed installations, which makes contact export difficult. Most manual methods depend on Outlook availability.
GainTools OST to VCF Converter works independently and does not require Microsoft Outlook installation. You only need to add the OST file, preview contacts, and start conversion. The software reads OST data directly and converts contacts into VCF format in a few steps. I used it when Outlook stopped opening on my system, and it still extracted all contacts successfully. You can download the free demo edition to test the conversion process before upgrading.