This worked!!!!! OMG!!!
Converse with fellow players
I'm in same identical position waiting on support ticket. I did get into game x2 last weekend using PSO2 Tweaker but it was not consistent. Win 10 and thru Steam. Did have exceptions for AV and Firewall for PSO2. Tried changing from Slave Drive to Main but no change. When I did get in last weekend using PSO2 Tweaker - I basically followed these steps: 1) I had temporarily disabled Public / Private Firewalls as an extra step , 2) ran the GameGuard Fix, 3) ran the check for missing files (since it seems to miss a file needed for gameguard, then run game. Let me be clear, it was not consistent before (2 attempts in that Gameguard actually updated correctly out of 60+ is poor) and that method hasn't worked since last Sunday.
Whether I try to play it thru Steam or PSO2 Tweaker, I always get stuck at the same point as listed above (EXACTLY).
Something Permission wise with Gameguard is blocking entry into the game and there is not exceptions left I can use to allow Windows 10 to allow access for Gameguard thru how the game is setup. I've reinstalled more times then I care to admit but it always gets hung up at the same place consistently whether i use PSO2 Tweaker for Global Steam or Not, just from Steam itself.
I put a support ticket in and have encouraged a ton of people on the Steam Forums that are complaining about the same exact program problem to do the same.