Protected Mode causing slow opens

Hi,
I have Windows  64 bit and Acrobat Reader.

Acrobat Reader hangs for an extended time when opening (even just the app, not double clicking a PDF) with 'Not Responding' with Protected Mode turned on (off it works fine)

Its very frustrating when you need to open several files just to check a small detail.

Have googled, but found nothing concrete, seems a lot of folk suffer with this issue  - a short mention is made of 'delete temp folder', - but without any details, but am not sure where that is located, is that also related to 'autosave' ?
Some suggestion of Network Folders made, could the App be trying to access one of those folders - which might be offline, with a temp autosave version ??? 

Bit stuck, any ideas ?? wasting a lot of the day on this.