I got a 1 TB disk a year or so ago and loaded it with some hundred of GB of data. I somehow neglected to check the file system, which turns out to be FAT-32 and thus too small for files bigger than 4 GB. So now I want to change it, without deleting the data. I thought I'd just make a new partition in the so far unused space. Then with the new partition, copy/move the data into the new partition, and then delete the old FAT-32 partition, and make the new partition bigger again... or just make a few more partitions. The critical step here is, can I make that new partition without ruining the data? The data should be fairly sequentially added to the start of the disk, but what do I know... so that's why I'm asking. Can I safely use Disk Utility for this? Any recommended file system?
Open Disk Utility, click the drive, then click the Partition tab. Resize your current partition and create a new one by clicking the + sign. DO NOT click a new Partition Layout, or that will erase your current partition.
Use a Gparted boot CD from here. I'm usually a skeptic, but resizing a FAT32 partition should go well. However you can never be sure as there is no partition tool on old ma' Earth that won't present you with horrible "you may loose all of your data" or "you are on your own" warnings.
So the list would be:
If everything is working fine upto entry #5, I wouldn't delete that FAT32 partition but resize it to a mere 50-100 Mbytes (As I'm super skeptic).
Plan B: Borrow a 1 TB external HDD from a friend, save everything and do a "format C:\"