I have a 1TB external that I've used to backup my Mac for the past year using Time Machine. Unfortunately, my hard drive is getting close to full, and I'd like to move some of the stuff off of my Mac onto the same external drive. The problem is that the external drive is already full with my Time Machine Backups. I'd like to partition 750GB to the Time Machine Backups, and save the other 250GB for personal use. Is there any way I can go about this without corrupting my current backups? I'm willing to delete some of the older backups if necessary; again I'm just worried about corrupting the data.
Is there any way I can go about this without corrupting my current backups?
Yes, you can make a new folder on the TimeMachine Disk and put whatever you like there.
Or, you can defragment the disk, this will push all the data to the (virtual) front of the disk, then you can make a partition at the end of the volume with the disk utility tool in OS X.
The only benefit to the second option is that you'll be able to keep TM confined to only using 750GB since it will attempt to use the whole disk.
You can also create an image on the external HDD - Using Disk Utilities - Create New Blank Image and select the amount of space you need. Then you can mount the image and read/write to it with your personal files. Because it takes up space on the HDD Time Machine will not erase it or overwrite it.