In this guide, I will show you how to get enter a solo session 100% of the time without much hustle.
Step #1: Joining a Session
Join any GTA Online session. No really, any will do.
Step 2: Task Manager and GTA.exe
Before we proceed on the actual method, I want to inform you that it might seem that the game kicks everyone out of the session. What actually happens is that the game kicks you from your current session and puts you in a different, yet empty session. That means that what ever unsaved progress you have in your current session (On-going MC missions, CEO special offers, VIP work and so on) will be lost. I learnt this the hard way :)
Now to the actual method
While you're in a session, open Task Manager. Head on to Performance, then to Open Resource Monitor on the far down left. Once you're in the Resource Monitor, it should look something like this:
Step #3: Finalizing
Now, scroll down the list until you find GTA5.exe. Right click on it and click Suspend Process as shown below:
Wait for approximately 5 to 10 seconds, then scroll to find GTA5.exe. Right click on it again and click Resume Process as shown below:
Return to your game. Now it should look something like this: