I have a tarrasch database in a tdb file that I would like to run into my scid-vs-pc gui. But after spending a lot of time looking for some information on Google, I found nothing that can help me. How do I to convert tarrasch-base.tdb into pgn for scid?
The Tarrasch Chess GUI is an open source, free Windows download. It uses a proprietary database format and the author approached Mark Crowther, the brains behind TWIC to ask if he could use Mark's database of games. Mark agreed but part of the way Mark makes his living is by selling his full database. There is an export to pgn format function in TCG but to protect Mark's work this feature is limited to 10,000 games.
So, provided your tdb consists of fewer than 10,000 games you can download the program, import the tdb database and then export as pgn. If, on the other hand, you are trying to rip off Mark Crowther's database you are SOL (out of luck). If you are determined to deprive Mark Crowther of his dues for developing his database then your best bet is to download the TCG source code, extract the code for pgn extraction and modify it.