My After Effects freezes and crashes all the time. Whenever I try to preview the composition in "Full" quality, it renders a few frames and stops working. Often when working in AE, my taskbar disappears and AE just becomes blank/white. Sometimes it turns screen black and I have to restart my laptop everytime when it happens.
Model: ASUS N551JX
Processor: Intel(R) Core(TM) i7-4720HQ CPU @2.60Ghz 2.59 Ghz
To be frank 8GB of RAM really isn't enough to run AE fully. There's barely any space in your memory to buffer those frames you're trying to view.
But go into settings and try to change your RAM settings to allow AE to access more of it, that should help with your frame buffering, but... again... you need more RAM.
As for the crashing of the side bar, I will say since the update I've been having loads of issues with the new version of AE on my PC (I use a Mac for mobile editing and a PC for office editing, runs fine on my Mac).