I have a new 2TB Western Digital external hard drive (My Passport Ultra) that I want to use for backups. I have it formatted as Mac OS Extended, with 1 Apple Partition Map partition.
When I Get Info on it, it says "you can only read". Next to my username, it says that I have Read and Write. I am unable alter any of that when I unlock the lock. I also can't seem to do it from the command line with chmod/chown: the file system is read only. The laptop is a MacBook Pro (Mid 2014) with OS X Yosemite (Version 10.10.5). Finally, my friend with an Air with the same OS can use this drive without any issues.
Any suggestions on how I can figure out what's wrong and fix it?