Maybe this :
-If you own Digital/Ubisoft Connect download version of the game, you'll have to perform manual sh5.exe replacement
before you proceed to TWoS installation. Valid v1.2.0 sh5.exe from DVD version of the game can be found on this link...
http://www.mediafire.com/file/x48vge3whjf4ua5/sh5.zip/file
-Ensure that SH5, Uplay or Steam are not active in the background while installing the mod!