Sorry for the delay. I redownloaded it and tried it again and I had no such problems. Only thing I can suggest is try running it as administrator and make sure your virus protection isn't affecting it. I would appreciate if you shared the error text so it can observed more closely. I'll tell the creator about this and hopefully he'll have an answer.
The error text is the one I originally posted, "Unable to read the database. It seems to be corrupted." No more info on the error log...
No luck running as admin.
Also
ManRT, I forgot to ask you the same thing, but what update of GT5 are you on as well?
I cant' tell you now but my problem starts in the .exe file, it has nothing to do with the update, or maybe I'm missing something!
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Anyway, I've been playing a few hours but I bought and installed Gran Turismo 6 too, and it looks like every downloadable car from GT5 is in GT6, so I'll be able to play with them x-) By the way, I spent around FIVE hours installing/updating Gran Turismo 6 (!)
It's ok to play between games, I've been riding a lot in Tourist Trophy too, two days ago I finished the last championship, something I should have done many years before!