There is probably no way to open a TurboTax .tax file from 1999. The only way to open it would be with the TurboTax software for 1999. That software is no longer available, and probably would not work on any current computer even if you could find the software. There is a company called TaxPrinter, not affiliated with TurboTax, that can create a PDF from many old tax return files, but their website says that they cannot read a TurboTax file from 1999 "for technical reasons."