New here and I registered with this site to post this thread to help others I hope.
If you don't want to read my story, skip to the bottom, the resolution is there.
Running Windows 7 x64, an older gateway GT5232e machine (OHhh I know not the best, but works).
My quick story:
Computer crashed (ended up bad ram), so bought a new WD 3tb green drive (from FS) as a storage drive for media and making my WD 1tb black my main drive. Install it reboot machine and of course as many others have stated I had the issue with seeing the full 3tb. It would only read 746 gig, with no information of the remaining hdd. I could NOT find it for the life of me. I used WD tools to find it, I used diskpart.exe to find it, partition it etc. I did change the 746gig to gpt, but still nothing. Tried reinstall with windows 7 x64 wouldn't find it. I spent a few days on it urg. So I took it back and after researching, figured the seagate Barracuda 3tb because they have their own tool (discwizard), that is suppose to find it if you have these kinds of issues.
WELL... took it home and same Freakin problem. I used the discwizard, seatools and it would only read 746gig, nothing more. Tried more or less the same stuff all over again and more research and nothing. I was done with this so was going to take it back and just get a 2tb drive. I got the 2tb drive and of course worked great! But when I was at futureshop I asked the tech there to see if he could format the 3tb for me and in hoping I would be able to see it on my computer. WELL he couldn't find it either, and tried 2 different machines.
SO... took that drive (seagate) back to where I bought it (canadacomputers) told the tech there, he put it in his machine and saw it right away and I had him format it in to 2 partitions, 200gig and the rest as another partition. Took that home, plugged it in and BAM I could see both partitions so I'm happy. I start transfering files to the main 2.4tb partition. Thinking all is well... Well FML it would stop at 1.99tb free. It froze so tried again, and again, after some test realize there is a problem. Go to reformat/repartition and BAM back to 746gig and can't see the rest.
Are you kidding me... so more research... I actually installed a program with driver scannner and told me what was out of date. I finally got my bios updated (the instructions from gateway didn't work worth crap), don't think I needed it tho. I updated my motherboard/SATA drive (Nvidia nforce) to 220.127.116.11 the latest driver (so I thought). Still not working. The driver scanner still said my SATA was out of date, and Nvidia site wouldn't reconize my motherboard so I had to do more research to find out what the most up to date drive is.
Which is 18.104.22.168, reboot and BAM.. I can see my freakin 3tb drive. I can format it, partition it, whatever I want with it now. I can transfer files to make the drive less than 1.99 tb, so that problem is solved as well. It is formated now in 2 partitions in GPT. HURRAAAYYYY!!!
IF you are having a problem with detecting your 3TB drive, update your motherboard/SATA drive!!!!!!!! I wouldn't even bother with your bios to start, as I don't think it is required. Make sure you check what version you are running and have the most updated driver for you SATA/motherboard, Change the partition over 2.2tb in GPT and format. Done!
FOR Nvidia nForce the latest driver is 22.214.171.124. Just google it (nvidia nforce drivers 126.96.36.199).
As for other motherboards.. I don't know them, but google it and I'm sure you can find the lastest ones.
I really hope this helps, as I did not find this specific information when doing google searches.