The launcher works fine, & when I click on play, the intro movie starts, but audio is not synched. Once the intro movie's done (or when I press escape) I get a loading screen, and then return to desktop.
I tried checked if there was no problem with the install, then uninstalled and re-installed, all compatibility modes, launching as admin, launching the game directly and not the launcher, nothing worked.
I also tried to disable my second monitor, change to various resolutions, & it didn't work either.

I use a Windows 7 (6.1 v7601) under Dx11.
Please help?

Unfortunately I'm unfamiliar with this problem. If you haven't yet, send a support ticket to GOG via the "support" tab at the top of the GOG website. They sometimes take a short while to respond, but should be able to help you troubleshoot the issue.

I had the same problem, or close to it since my game didn't crash. It just hung forever after the Ulukai symbol on the loading screen filled up completely.

After some desperate deep digging (I love this game!), I think I finally found a FIX!

Turns out the game loads some DLLs to play sound/music. In my case, the last action of the game's .EXE file was that it tried to load/use some DLLs of Corel WinDVD 10, a software that came bundled with my Lenovo Workstation. I renamed the main folder of WinDVD (which contains the DLLs that Outcast tried to load) using a Windows 7 Recovery DVD via command line. This is because Windows wouldn't let me do that ("some files are in use"), even when booted into safe mode.

Now the game starts like it should, including sound and music!

I may give detailed instructions on how I was able to pin down this problem to the DLLs in question, since others may have different applications installed that are to blame. I hope this problem will eventually be fixed in another update to Outcast 1.1. Please let me know if any of this was helpful or not.