Converting an External Hard drive to NTFS

I am trying to convert my external hard drive from fat32 to ntfs. If possible, I want to avoid losing the data or having transfer it off and back on and formatting ( I have about 400gb of data).

I am using windows 7.

[The hard drive is a samsung story 1.5tb drive] It arrived in FAT32 but I did not check this and began using it. For the past year I have been using it without any problems. Only recently had I started to deal with large files and suddenly I noticed that it is not ntfs and that fat32 has a 4gb limit.

I have tried:

1) opening cmd as administrator and doing a conversion there e.g: convert E:/ fs/ntfs
This failed. It said messages about the drive being in use and asked me if i wanted to kill these connection i entered Y and it would not convert.

2) I ran chkdsk everything was fine. Tried again as above.. failed to convert to ntfs.

3) I searched for third software to do this - i have in the past used 'partition magic' to do this but i noticed that this program is very old so i found 'EASEUS partition master' it was not able to convert it.

4) I restarted in safemode command prompt and ran the convert E:/ fs/ntfs command from there everything seemed to go right up to the last minute and then it failed to convert.

Are there any other methods other then the obious "move the data off the drive format and place it back on" route.

Answer

Thanks for the responses guys! But I fixed the issue myself in the end...

What I did was use this command:

convert E:/ fs:ntfs /NoSecurity /X

This action disabled the UAC by disabling security and allowing all user access. /X dismounted the drive before conversion. It attempted the conversion. Chkdsk found errors on the drive.

I then ran this command:

chkdsk E:/ /F

(/F fixes any errors on the drive automatically)

It worked and fixed two corrupt file errors in insignificant files.

I then finally did the original command again:

convert E:/ fs:ntfs /NoSecurity /X

Conversion was successful this time and took about 20 minutes in total.

I can't begin to imagine how long it would have taken to copy 400GB from the drive via USB, format the drive and then put the data back - I guess DAYS!

Thanks again for your responses; I hope someone finds this useful in the future when trying to convert an external hard drive from FAT32 to NTFS without losing data.