App Crashing More Than Ever, When Syncing.

Hello, 

first time posting here because usually I find a work around. Not this time, 

I was using the PC version, when it suddenly crashed and displayed the 'send error report' message, photos were uploading at the time, they never finished and have since been cancelled and deleted. Now LR (5.3 at the time) will not stay open or just do anything useful.

it has since then been reinstalled twice, updated now to V5.4, graphics card options looked at... using other devices I've purged the storage used right down etc...

what I have found, is when the Pause Syncing (despite there being no changes) is hit, or when I'm in areoplane mode, Lightroom works fine, but the the moment it's reconnected to the cloud it crashes instantly. 

if anyone has some suggestions on what seems to be cloud based effects on Lightroom, please drop them below. 
thank you