Mode Switcher with my X-Fi Xtreme Gamer doesn’t work when I exit AC. The Mode Switcher console will not switch from Game Mode back to Entertainment. The problem occurred after I exited AC the proper way or Alt + F4. I got an error message that reported, “This operation cannot be carried out. This may be because the audio device is in use. Please quit all audio applications and games, and try again.” Sound driver is updated. I opened Windows Task Manager to end process, but I didn’t see any applications running, and didn’t recognize any processes that I could end. The problem resolved by computer restart. Don’t want to restart each time. Thanks in advance for the assist.

AC is rock solid. If not for the wide screen/full screen issue or this minor sound issue I would say Ubisoft struck gold with AC.

quote:

X-Fi Xtreme Gamer

whats the point to switch back?
In Game mode all the sound processing unit works fine for all 100%)

But anyway its common problem with Creative software bundled with drivers, not only u experiencing this problem, and its not only present with AC, there are many other OAL\DS3D games that causing this stuck in "Game mode", thanks do Daniel K who did Revolt in Creative policy they working much better on drivers and software now, but still u can only hope this will be fixed in next releases.
Cause of this may vary on different systems: opened thread or unloaded Dlls usualy.

Also try this method to unload unused dlls:

Open up Regedit.exe (dunno if u know how to do it, if u dunno then START>>RUN and type there Regedit)
find there
HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer

Then look for DWORD value named AlwaysUnloadDLL if its set to 0 change it to 1, if its not exist by default its 0, so u should create this DWORD parametr with name AlwaysUnloadDLL and value 1.

Reboot and try if this helped, also keep in mind that there are several programs that cannot handle loaded dll`s to say simly "well", they may crash, if u will experience lots of crashes then better rever to 0 value.