Can't modify external hard drive partition with Disk Utility

[augu2000]

Hi,

I have an external 750GB hard drive that I previously formatted as FAT 32 because I wanted to be able to plug it into Windows computers as well. I was not very thoughtful at the beginning and I just created one big 750GB partition. I currently have 450GB used and about 300GB free.

I would like to create a new partition in the free space without losing the data I have in the disk, and format the new partition as Mac OS Extended to use it for Time Machine backups. Presumably Disk Utility can do it, but when I go to the "Partition" tab it says "This partition cannot be modified" and the "+" sign below it is grayed. Can anybody help me repartitioning my drive without losing my data?

Thanks!!!

 

[Vantage Point]

Sorry. you can create partitions but the drive itself can only be in one format. So if you format for Mac you will lose everything on the disk.

The good thing is that if the disk is only storing data I believe both Mac and Windows can read it but only one can write. So formating for Mac lets Mac read and write, will Windows can only read - and vice versa

 

[augu2000]

Hi,

I believe there is some other problem (besides not being able to use different formats in the same drive) because I am not able to add a partition even if it is in the same format than the existing one. My guess is that FAT32 partitions cannot be resized with Disk Utility, but I am not sure on this.

 

[Vantage Point]

I have resized and added partitions without losing anything but it was Mac formatted. Also, if you have several partitions you can really only resize the bottom ones not the top ones.