As title say's, when at the first loading screen when I boot up it loads a little of the bar and doesn't move. Anyone else getting this?

It has been noted in other threads that it just takes a lot of time, the first time you fire it up. Let it sit for a while and see what happens, is my advice.

Only the first time? Oh boy, I wish.

EDIT: Also, the loading taking forever is just part of the problem─It has already frozen on startup half a dozen times today, plus once more while trying to load a saved game. Yesterday I managed to play without a hitch (other than the invisible text bug), but today I still haven't been able to.

I walked away and left it and still stuck - how long is long? A day, two days :(

I hope it's getting looked at

Right, I walked far away this time and it did indeed start. Quit and tried a second time, and then a third time, and both took exactly four minutes so still not great really

This happened to me after the latest patch (1.2.6). I have waited around 40 Minutes, rebooted my PC and tried again, to no avail. I have a relatively recent PC with an SSD hard drive, so I don't think the problem is hardware related.
Would really like to find a solution that does not involve reinstalling the whole game...

P.S. And no mods, absolutely no mods installed.

I got a very quick reply from the GOG support team to my inquiry and the problem is solved. Basically, they asked me to delete the Windows registry key of the game. Below the instructions for others who may face a similar issue:

"Please open the registry editor using the Run... window (WinKey+R key combination) and entering:
regedit
go to:
HKEY_CURRENT_USER\Software\Owlcat Games\Pathfinder Kingmaker
Please remove the entire Pathfinder Kingmaker key and then please try to launch the game again."

Great support from the GOG team. Thanks!