Read only access issue after time machine migrate

Question

Having a small issues on my new rMBP. I recently switched from my MBA to this newer rMBP and I previously had a Time Machine backup that I migrated over. For some reason though..when accessing my external hard drive it keeps asking to authenticate the user and I have to put in a password anytime I edit or add files to this external drive. I was also having issues running some commands in Terminal where it said I didn't have access..my current user shows up as being admin but I'm not entirely sure how to get past all these restrictions and have read/write access  to everything.

Answer 1

So I looked at the above images and noticed that the disk labeled "HD-PATU3" is almost entirely full - only 5GB of 1TB is available - so it's essentially "full".
You said that this drive "was" used for Time Machine backups - is that still what you want to do with it in addition to your own files? If you do still want to use as TimeMachine that's OK, but you can't predict what TM will do with it as far as space goes unless you split the disk into two partitions. TM knows how to remove old "snapshots" to make room for new backups, but do you need space on there as well for your own stuff?  Some people think it's not a good idea to mix your own stuff and TM stuff on the same disk volume, so that has to be your decision to do.
You might want to take a look at http://pondini.org/TM/6.html and read what he has to say (Pondini is a TM expert/god/phsychic - basically he recommends splitting up the drive into two partitions - one for TM and one for you - that way things are easier for your data as you don't have to live with issues the TM enforces on it's backup volumes. So answer the questions:
     1. how large is the internal drive on the rMBP?
     2. how much do you want the external drive to have for backups and your stuff - in fact is there a reason why you don't have all
         stuff on the internal drive? There are performance penalties for having your data and TM backups on the same disk. You
         probably have a nice large internal disk on the new rMBP so is this really what you want to do?
     3. Depending on the answers we can get more specific to solve your issue(s)
later......