My answer, to help people on getting a better approx time for the process.
I have just converted a 1 TB external hard drive from fat32 to ntfs, having about 200 GB of data, and it took about 50 minutes.
however, instead of directly using a command in windows (seven), i used this tool: partition wizard. Anyway, i guess the only difference is that those partition utilities (there are several similar utils, like easeus ) use the built in windows commands, but they do it for you, so you only have to give a few clicks in a nice UI
I was afraid of losing data, since the drive is actually for backups, but it went pretty well, and i expected it to last MUCH longer (i imagined like 3 hours or something). That is precisely why i am giving this answer, to let people better estimate the time it will take for their cases.
For your case, with 500 GB of used space, it may take a couple of hours.
Anyway, as other answers say, there is always a risk, and it is a good idea of having a backup elsewhere, or just take the risk, but don't complain if something gets wrong =)
Oh, and what not everybody mentions, is that you NEED to have some free space in the drive/partition to make the conversion, if you have an almost full disk, it wont let you continue. In my case, having 200 GB used of 1000 GB, it asked for about 1.5 GB of free space, so i had no problem, but other cases may differ.
2Same here, have done dozens of them and never had an issue. However, if something happens during it, it is probably going to be VERY bad. Have appropriate backups first. – Brian Knoblauch – 2010-09-23T17:03:35.653
1Okay, problem is I don't have anyplace to backup all 500 GB, my other drives are also filled. Is there a way to split large files, transfer them and reassemble them on the NTFS drive? – Rakward – 2010-09-23T18:17:45.873
1@Rakward: sounds like you need to do some risk management. Find the files you can't live without and back them up. Take the risk with what's left. IF you can't back up the files you can't live without then you absolutely need to buy another drive. – hotei – 2010-09-24T03:30:44.343
Fine, you can't have to many back ups anyway right. Thanks for the help. – Rakward – 2010-09-24T07:59:59.973
Thanks for the question-er and answer-ers it helped me decide about my disk usage tooo:) – Ravisha – 2011-01-11T11:46:44.080