If upon starting your GMAX you get an error message like "Interactive 3D Renderer initialization failed. Please check your device settings by using the -H command line option", don't panic. It's not realy a problem. It is just a warning and it is giving you the solution at the same time.

What does it mean ? I means that the rendering driver you choose at the beginning isn't able to display correctly on your screen.

What's the solution ?

You can do it in 3 ways :

A) FROM INSIDE GMAX
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1) click in the top menu CUSTOMIZE
2) in that menu, click PREFERENCES
3) you will get a pop-up with a bunch of of options. Click the top one that says VIEWPORTS
4) in the bottom right corner, click the button CHOOSE DRIVER
5) another pop-up appears with choices of HEIDI, Direct3D and OpenGL. One should already be chosen. Choose another one.
6) click OK then the OK button of the other pop-up
7) if your viewport still doesn't work, try another driver.
8) if after trying all drivers it doesn't work, post a reply here indicating it.

B) FROM OUTSIDE GMAX
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1) find the shortcut you use click on to execute your GMAX(if you don't have one because you click on the GMAX program icon directly, then do create a shortcut)
2) do a right click on it and choose PROPERTIES in the menu that appeared
3) a pop-up will appear. Click the top tab SHORTCUT
4) in the TARGET field, you will have something like "YOUR DRIVE:\...\GMAX\gmax.exe"
5) before the ending double quote, add -H (dash H)
6) click OK
7) execute your GMAX via that shortcut you have just modified
8) the GMAX logo will appear. Wait a bit ...
9) another pop-up appears with choices of HEIDI, Direct3D and OpenGL. One should already be chosen. Choose another one.
10) click OK then the OK button of the other pop-up
11) if your viewport still doesn't work, try another driver.
12) if after trying all drivers it doesn't work, post a reply here indicating it.

C) NO CLUE ON HOW TO DO SOLUTION A OR B (risky solution so be ware)
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1) start a text editor (Notepad will do nicely)
2) open the file ../gmax/gmax.ini or ../gmax/gamepacks/your_gamepack_folder/gmax.ini
3) do a FIND on "[WindowsState]"
4) the current rendering driver used will be coded as follow following that string of character you found

[WindowState]
GFXType=OpenGL

or

[WindowState]
GFXType=Direct3D

or

[WindowState]
GFXType=HEIDI

5) just replace your the value of GFXType by any of the three above that doesn't match what you already have.
6) save the file
7) start GMAX
8) if the screen is weird or blank or whatever, just close GMAX and choose another one.