I shot some raw images using monochrome mode on my Nikon D3200. When I transferred them to my computer, they appear in color. I cannot see the monochrome effect. What can I do to see the images in monochrome?
When you shoot monochrome as RAW files, the monochrome setting is just meta-data in the RAW file. The raw data from the sensor is still the same.
You will only see the monochrome effect when you view the file in a program that supports the monochrome flag. Obviously what you are using to preview the images doesn't support it. The program from Nikon for converting RAW files would support it for example.
Almost all in-camera settings that affect image adjustments are irrelevant when shooting raw.
With raw, all image adjustments need to be controlled in your raw software instead of in-camera. The file basically contains the raw readers from the camera sensor without any adjustments.
What this means is that if you're shooting raw and want monochrome, you switch it to monochrome in your raw software rather than the camera. Whether you do it in camera will merely affect the camera's own JPEG previews/thumbnails but not the later result from the raw file.
There exist some mechanisms for the camera to "hint" to some raw software about certain settings. For example, most raw software can read at the very least, what white balance setting the camera used and emulate that same setting. Some proprietary raw software by the camera manufacturers may go further and may read hints in the file, reconstructing other in-camera adjustments such as contrast, tone curve (image mode), whether it's black and white/mono, sharpness, saturation etc. However, this isn't the point of raw, the point of raw is primarily that you set all these in your raw software instead and thus have greater control, bypassing the camera's mechanisms for adjusting the image.