It doesn't seem to be possible to anyhow convert NFB backups to VCF contacts. However, you may have been looking to convert NBF backups as VCF contacts.
I that's the case you can use the Nokia PC Suite program to export the contacts from an .nbf file to a CSV format and then use any of the available CSV to VCF converters to get your vCard contacts file.
This conversion entry was verified by us and conversion was flagged as wrong or not possible.
Usually this happens when the conversion would try to convert different types of data between each other, such as audio to image, or it is not possible because incompatibility between programs, caused by closed file formats, very limited support etc.
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