If you want to play games like Schedule I, R.E.P.O. or others with friends, you have to install an Online Fix.
Open Online-Fix
Do not click on any ads — they may contain malware or malicious links.
Select your languauge
The website is in Russian, so if you don't understand Russian, choose English in the top right corner.
Register
You need to register to access any of the download links. Hover over the Register button and choose either Google or Discord.
Find your game
When you’ve found your game, scroll down until you see the Download buttons. Click on the Download from Online-fix Hosters button, and the download page will open. Select the file that has the following name: [Game Name]_Fix_Repair_Steam_V[Something]_Generic.rar
Download WinRAR
If you haven’t already, download and install WinRAR using the button below.
Drag the files into the game’s folder
Open the game’s folder (How to open Steam game's folder?), then open the the .rar file you’ve downloaded. The password is online-fix.me. Select all of the files inside of the .rar file and drag them into the game’s folder. When a window like this pops up:
Click Replace the file in the destination. It could appear multiple times.
Congrats!
If you’ve followed all of the steps correctly, you should have online working.
When you start the game, Windows Defender might detect a “threat”. Dismissing a false positive in Windows Defender