Apple - Convert a partition from case-sensitive to case-insensitive
iPartition claims to be able to do this, although I haven't tried it (and it costs money).
I converted the default case-sensitive HFS+ partition to a case insensitive one after discovering the problem after installing a new MacBook. I assume here that you have enough disk space on your internal hard drive to duplicate the data and system files that you already have installed.
- Use Disk Utility to shrink the size of your existing boot partition to just big enough to contain the existing files.
- Create a new partition that is only Mac OS (Journaled) and is NOT case sensitive.
- Backup the original drive to the new partition. I used SuperDuper! but you can use rsync.
- Boot holding down the Command key and select the new partition.
- Delete the old partition with Disk Utility and increase the size of the new one.
I don't believe its possible to convert your file system once this is selected. The reason you can't convert is because of the possibility of file name duplicates. All you can do is clone the drive to an external HFS+ that isn't case sensitive and then format your internal drive. And clone it back to the internal.
I would recommend using Carbon Copy Cloner for its ease of use and the fact its free.