I recently deleted a few partitions (Linux) after removing them, I was left with a lot of freespace. Everytime I try to add it to Macintosh HD, it gives me a prompt saying it can't. Is there anything I can do?
To resize (or delete) an existing partition without losing data, you will need to use, for example, iPartition:
Make a bootable clone of Macintosh HD, then boot from that to repartition, then clone back again. Carbon Copy Cloner works.
try this: http://flarn2006.blogspot.com.au/2010/09/grow-hfs-partition-on-mac-os-x-without. html
This wouldbe my approach (above). Cor clarity:
1. make a full, bootable clone on an external drive
2. boot from external drive, partition and format internal HD
3. clone back
Retrieving data ...