I've searched for some combinations of keywords but all I could find was a fix to the black screen after you switch back to Skyrim or how to get rid of the double mouse curser bug, but not even once how to disable Alt+Tab.

Is there a setting that deactivates Alt+Tab while playing Skyrim?

Solutions i have found:

When you get to the empty window, Alt+Tab to the Skyrim window again. This will bring you back to the game.

Alternatively, you can use Ctrl+Shift+Esc to open the Task Manager, right click the Skyrim entry in the Applications tab, and select Bring to Front.

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Actually, there's a much easier method of getting around this. When going back into the game, when you would normally click the game's window to go back to full-screen,

drag the window down an inch or so and it'll go back to full-screen - this will always get rid of the cursor.

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Another way to fix this is by pressing Ctrl+Alt+Delete, pressing 'Cancel', and then trying to re-maximize Skyrim. That works every time for me.

That's a function of your operating system. If you want to completely disable it, you have to make a registry edit (Start/regedit/return).

This is the change for Windows 7

Hive: HKEY_CURRENT_USER
Key: Control Panel\Desktop
Name: Coolswitch
Type: REG_SZ
Value: 1 enable switching
Value: 0 disable switching

For a different OS, use Google.

Better yet, just refrain from using it.