Hey Everyone. Today, I installed 10.9 on my mid 2011 Mac Mini. It was having some issues being a media center and switching to it's HDMI output for sound after the most recent OS X update. (The one with the security patch.) as well as numorus other errors that I wasn't able to point point a fix for. So both dad and I agreed that a fresh install would be a good idea. Instead of using time machine to back up everything, because I thought that would lead to the reoccurrence of some problems we were facing, he chose to instead move his personal folders and files himself while I helped him with applications and application support folders. everything seemed to be running smoothly untill we encountered problems with the drive it's self. I should preface a little here and say that this particular external hard drive, a USB powered 1tb Toshiba, had been giving us some red flags before. It had to be completely formatted once already after disk utility couldn't fully repair it. We mused on the idea of getting a new, better, thunderbolt drive but that wasn't the route we ended up going. So dad uses this external drive to back up everything. After a few initial tests to see if application settings i copied still work, as well as designating the drive as a time machine backup (Which i think might have been a bad idea...),i leave him to put all his personal folders back in place. Then he starts to encounter even more problems even though disk utility says the drive is passing all it's tests. These are the two most common errors: This one occurs when trying to modify or put any information on the drive. When creating a folder or trying to add a file from the internal drive, the error code is -50. When trying to rename a folder/file, it simply tells me to use less characters (Which is basically telling me i can't do it at all.) https://31.media.tumblr.com/afe64d0382fb72579477f1f139bb36a7/tumblr_n1ydxmelM21rw02spo2_500.png This second issue is the most problematic one. When Transferring large folders from the external to the internal (which is can do some of the time) the following error occurs after a while. It seems that the folders cannot complete a transfer in their entirety. It's an issue we can work around, however, but i would still like to get to the root of this problem so it could be fixed. (so i don't have to transfer and keep an eye on every single file myself because we eventually declare this drive a dead-pushing-daises-decased-dead-parrot drive. https://31.media.tumblr.com/02881f6a57c2d8a66ab8e8f9cbca4756/tumblr_n1ydxmelM21rw02spo1_500.png In an effort to troubleshoot before sending this post, I plugged into my 2012 Macbook pro and these problems simply didn't exist. I was able to transfer to large folders filled with pictures with no errors. (also learning that wow my macbook has USB 3.0 how about that) After plugging it back into the mac mini...it works. No more errors. haven't tried transferring larger files, but i have a sneaking suspicion that this will happen again We're already not going to use the drive for any purpose after dad gets his backups off of it, but in case the errors come again, or if you'd like to solve this mystery with me, i'm posting this thread anyway.