How to Fix M.A.T Error I3

1. Go to the MAT official website and log in with your account credentials. Go to the "Downloads" section and scroll down to the "Manual Patch Files" section.
2. Click on each patch and download it to a folder on your hard disk drive -- "2.1.6.334 - 2.1.6.335" is the latest patch at the time of publication. The patch names suggest the order in which you must install them. All patches come as executable files so you can easily install them.
3. Go to the folder where you saved the patches and double-click the "MAT update318-319" executable file. This is the first patch you must apply. Click "Run" if "The publisher could not be verified" security warning appears. The "Welcome" screen should appear.
4. Click "Next" in the resulting window and type the path to the folder where you installed MAT in the "Destination Folder" text box. Click "Install" to start installing the first patch. Once the installation is complete, close the window.
5. Install all the patches in order. Start MAT and connect to a server. The "error I3" will no longer bother you.