The game runs fine beside one problem,
if I buy food or loot enemies and enter another city or village my whole inventory is empty. Everything is gone.
Does someone have an idea how to fix that problem?

I can't help you, but someone else might better be able to if you mention which specific game you're talking about. ;)

Mount and Blade Warband

I have a similar problem. I had this game for months and played it frequently. However, my hard drive died and I had to download and install it all over again. After the new download and installation, the game gives me an error code 560 and it keeps erasing my inventory and it somehow defaults all factions having 100 loyalty. Is there a patch available?

I've reported this on reddit and just randomly found this here as well.

I'm glad I'm not alone. I also have this problem and it's driving me crazy. I created a video of it which can be found on youtube under the title: "Inventory bug - Mount & Blade: Warband 1.168"

(unfortunately gog doesn't let you post links)

Only because your forum rep is too low (it's an anti-spam measure); you can post links when your rep hits somewhere around 7-10.
You can work around it for now, if you like, by inserting spaces (https ://www. youtube. com/watch?v=J4ilotO0ZrM [your video, BTW :) ]), spelling out certain parts (gogDOTcom), or similar.

Just so peaople don't have to copy-edit-paste to view your example video, here's a proper link: https://www.youtube.com/watch?v=J4ilotO0ZrM