I had the same problem until I realized the real problem was something else. What you're seeing in TT RGB Plus (screenshot and video) doesn't mean the fans haven't been detected, it means they are deactivated in the user interface. If you click on the little red circle to the left of the fan name, it opens the configuration interface. In the same way, if you click on the little green circle next to the fan name on an open interface panel, it will close it.
So far, so good. The problem I'm having is that the same two fans are always deactivated again (red circle, config panel closed) every time I reboot my system even though I saved the settings and even checked the readable .ini file to make sure the settings were saved to that. Unfortunately, TT RGB Plus doesn't seem to care that the .ini file indicates all 5 fans should be activated (green circle, config panel open). So I have to manually open them again every time I reboot if I want my fans to work the way I configured them.
The .ini file can be found at C:\Users\<UserName>\AppData\Roaming\Tt\RGBRiingPlus\Device.ini
The line I'm looking at in the file is "Monitor="1,1,1,1,1". My own testing has confirmed that this is the setting that is changed after manually changing the "red circle/green circle" I mentioned above. However, manually changing the value in the file while the App is closed doesn't seem to have an effect on the settings the next time I open the Application.
