When I alt+tab while in game i my client crashes?

not enough computer resources. upgrade your RAM

I also have this exact same issue; started up right around the time the new client was being rolled out. On my end it is definitely a CPU issue. Only happens when I'm interacting with multiple windows at once and threads get reallocated away from the client temporarily.

then update ALL your drivers.

Graphics Card Manufacturer - Powered by AMD Graphics Chipset - AMD Radeon(TM) R8 M445DX Device ID - 6900 Vendor ID - 1002 SubSystem ID - 81FE SubSystem Vendor ID - 103C Revision ID - 83 Bus Type - PCI Express 3.0 Current Bus Settings - PCI Express 3.0 x4 BIOS Version - 015.049.000.012 BIOS Part Number - BR46776.100 BIOS Date - 2016/03/09 02:44 Memory Size - 2048 MB Memory Type - DDR3 Memory Clock - 1000 MHz Core Clock - 1021 MHz Total Memory Bandwidth - 16 GByte/s 2D Driver File Path - /REGISTRY/MACHINE/SYSTEM/ControlSet001/Control/Class/{4d36e968-e325-11ce-bfc1-08002be10318}/0000 Graphics Card Manufacturer - Powered by AMD Graphics Chipset - AMD Radeon(TM) R5 Graphics Device ID - 9874 Vendor ID - 1002 SubSystem ID - 81FE SubSystem Vendor ID - 103C Revision ID - CA Bus Type - PCI Current Bus Settings - PCI BIOS Version - 015.048.000.069 BIOS Part Number - 113-C75100-030 BIOS Date - 2015/11/02 22:12 Memory Size - 512 MB Memory Type - DDR4 Memory Clock - 933 MHz Core Clock - 720 MHz Total Memory Bandwidth - 29 GByte/s 2D Driver File Path - /REGISTRY/MACHINE/SYSTEM/ControlSet001/Control/Class/{4d36e968-e325-11ce-bfc1-08002be10318}/0001 Radeon Software Version - 16.6 Radeon Software Edition - Crimson Graphics Chipset - AMD Radeon(TM) R5 Graphics Memory Size - 512 MB Memory Type - DDR4 Core Clock - 720 MHz Windows Version - Windows 10 (64 bit) System Memory - 12 GB CPU Type - AMD A10-9600P RADEON R5, 10 COMPUTE CORES 4C+6G

This is so infuriating, as this happened to me once and League wasn't letting me reconnect, resulting in a leaverbuster. So mad.

Ok two things in case you've not checked.

First off check your physical memory. Ctrl+At+Del and it should show at the bottom if you're running windows. Often when I play LEague I have things like Chrome and Firefox running in the background playing music and the like and they tend to crash out if I'm playing as well (2 gb physical memory today when I checked it! Wtf is THAT about lol).

Secondly I've found when I close discord and league on the night and put my computer in hibernate, if I boot it up again some of the processess from the previous day are still open (again Ctrl+Alt+Del, processes tab). I've found in the past I've had 7 or 8 full trees for these which can REALLY fuck with your client! >.<

Hope this helps!