Hey,
Online free converters are usually limited and not safe, in particular, if you have some sensitive contact data.
Some of the issues commonly pointed out are:
The data is uploaded to servers that are not known.
The accuracy of the conversion is limited.
There is no accountability or support.
If you want to use it professionally, then it is better to use some offline tools that support VCF to PST Converter or VCF to NSF Converter workflows. That is the reason why users with sensitive data who put their trust in the DataVare vCard Export Import type of solutions, which operate locally and give more control over the contact conversion, are choosing such a method.
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