I just solved this issue for myself.
On Windows 10 I went: Start Menu>Settings>Update & Security>Windows Security>Virus & threat protection>Manage settings (under Virus & threat protection settings)>Turn Real-time protection off.
Real-time protection will turn itself back on eventually, so my solution is to always turn it off BEFORE launching PSO2. This solution has worked for me with a lot of issues in games. It has something to do with the read and write permissions your user account has while Rtp is on (which is to say, it restricts those permissions).
Hope this helps.