I'm sure many of you know how to do this already, but for those who don't, this will change your life.
The tutorial is laid out as simple as possible. Most people can just read the quick version of the tutorial to do it.
If you want the quick version go to the bottom of the thread where it says "All the steps in one".
Step 1:
Join a random GTA Online lobby. It doesn't matter if there are people there or not, just get into a lobby.
Step 2:
Go to your desktop. You can just press Alt+Tab.
Note: You need to be quick or you will get kicked for being idle too long.
Step 3:
Open the task manager. There are many ways to do this. You can either press Ctrl+Alt+Delete and click on task manager or you can press Ctrl+Shift+Escape or any other way. Just get it open.
Step 4:
NOTE: Make sure you have "More Details" on (the arrow at the bottom).
Click on the "Performance" tab (Located near the top).
Step 5:
At the bottom you should see "Open Recourse Manager". Click on it.
Step 6:
Find Gta5.exe in the process list.
Step 7:
Right click it and click "Suspend Process".
Step 8:
Wait for 7 seconds.
Step 9:
Resume the process.
Step 10:
Go back into the game and you should now be (or soon be) alone!
All the steps in one:
Join a public session. Open Task manager. Go to processes and open the resource monitor. Right click on Gta5.exe and suspend it for 7 seconds then resume the process. Go back into GTA 5 and you should soon be alone.
NOTES:
Make sure you have more details on in your task manager. Don't suspend the processes for too long or you will be kicked into singleplayer and make sure you do it long enough so it works. Don't be afraid to go for more than 7 seconds. You most likley will.
It is pretty simple. You are essentially lagging out of the session. Most people that have been playing GTA for a while have been lagged out of a session randomly, this is exactly that but we can force it.
I am not responsible for anything you do with this method or if anything happens to you.
There is no way for you to get punished for using this method. This is simply abusing a server connection feature.
Have fun!