Go to your Library > Select the game > Click Properties > Click Verify files .
A corrupted cache can cause various syncing and launching issues.
The quickest fix often involves forcing Windows to grant full read and write permissions to both the game execution file and the Ubisoft platform.
If the game is older, it may be looking for the DLL in its own installation folder rather than the launcher folder.
Type %localappdata% and press Enter. Delete the folder if it remains. Restart your computer.
Система не обнаружила uplay_r164.dll — решение