Do you also have any other Spyware/Anti-virus running at the same time? If so, could be a clash causing the crash!!
I have never used bitdefender, seen too many apparently associated problems.
Try with out bitdefender, for a while at least.
Surface Pro (2017) vs Surface Pro 4
Where HTML5 is headed next
MacBook Pro v Surface Pro 5
Synology invites you to visit them at Insomnia on 26th – 29th August. Book your tickets now and visit Synology.