Game sometimes stucks at 100% loading

My game sometimes just stops at 100% and i cant ALT+TAB or switch to any other tab. Only thing i can do is restart PC or switch a user on windows and then log again and enter the LOL cliant and hope it will not do it again. Few times i got reported couse it says that i am AFK in game and my game loaded properly. Soory if my eng is bad....

My PC specs: BIOS: BIOS Date: 02/20/17 15:21:58 Ver: 05.0000C (type: BIOS) Processor: AMD Ryzen 5 1600 Six-Core Processor (12 CPUs), ~3.2GHz Memory: 16384MB RAM Available OS Memory: 16336MB RAM Page File: 10068MB used, 9430MB available Windows Dir: C:\WINDOWS DirectX Version: DirectX 12 DX Setup Parameters: Not found User DPI Setting: 96 DPI (100 percent) System DPI Setting: 96 DPI (100 percent) DWM DPI Scaling: Disabled Miracast: Available, with HDCP Card name: Radeon RX 580 Series X2 crossfire 4GB Current Mode: 2560 x 1440 (32 bit) (144Hz)

Plz help!!