Macintosh OS/miscellaneous used space


QUESTION: Recently, I bought a TB external hard drive, which I partitioned into three parts.  Part one takes the Time Machine backups from my Macbook (13 inch, mid 2009, 2.13 GHz Intel Core 2 Duo, 4 GB RAM, OS X 10.8.2).  Parts two and three now hold my iTunes Media (tunes and pictures). I had about 100GB of media.  After I moved the files to the external HD, the "About this Mac" indicated that I then had 100 GB of Other.  I did a Secure Empty Trash. After that "ATM" indicated 100GB of Backups.  Grand Perspective identifies this block as "Miscellaneous used space."  This represents nearly half of the space on the internal hard drive.  This whole exercise was to free up drive space.  That hasn't happened.  What can I do short of reformatting the internal HD?

ANSWER: Richard,

I'm not sure, but I'm going to suggest that you properly eject the external disks and then restart your computer.  Once it restarts, reconnect your drives and see what you get.  

If that doesn't bring about the desired results, please try zapping your PRAM.  Tell your computer to restart and as soon as the screen goes black, hold down option-command-p-r.  Hold those down for 5 bongs and then let go.  

Whatever your results (good or no improvement), please get back to me and let me know what worked or that neither worked.  

Good luck!


---------- FOLLOW-UP ----------

QUESTION: Thanks.  (I hadn't zapped my PRAM for a long time.) Both those steps were logical, and I should have thought of them.  Alas, they had no effect. From other posts I've read elsewhere, the miscellaneous used space problem could relate to either Time Machine running when the laptop is disconnected from the External Hard Drive, OR it may result from countless updates of iTunes squirreling away copies of files.  Someone else theorized that it was all residual material from several systems upgrades.  This is apparently a common problem, judging from the number of posts online.

ANSWER: Do you want me to continue chewing on this one?  I can.  It's not something I have looked at recently but I can try to figure it out.  What is your pleasure?  From what you are saying, this has been a long-standing problem for a lot of people AND you don't seem to find a solution in any of their posts, eh?  


---------- FOLLOW-UP ----------

QUESTION: My iMac (24 in. early 2009) has the same 100 GB of unidentifiable used space on its internal HD.  It still has the whole iTunes library on it.  It also runs Time Machine and is never disconnected from the External HD.  Yesterday, based on something I read, I peeked into the /private/ folder and measured its size.  Nothing close to 100GB.  
Thanks for continuing to work with me on this.


Is there a reason you don't wish to reinstall the system?  Or is it you believe you need to erase EVERYTHING and not just do a clean install?  

I suggest you try a clean install so you get a new system with everything else remaining intact.  Of course, you would want to back up EVERYTHING before you began, but with Time Machine in place, that shouldn't be a big issue.  Because what I'm hearing is that you have this unidentified used space on your computer as well as the external drives.

I've read several posts but I don't find any that are hitting on your issue specifically.  And I am not up-to-speed on the latest systems.  I stopped at OS 10.6.8 because most of my programs won't run on the higher ones and I'm not in a position to replace them!  Alas, I can't experiment with your configuration.

If the clean install doesn't change anything, I strongly urge you to get in touch with a Genius Bar in an Apple Store.  They are free and if they can't solve your problem, at least it will make them aware of something they might want to explore and post in their FAQs.  I'm just not coming up with anything that seems to come close to your dilemma.


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Debba Robinson


AppleWorks 6, Systems up to 10.3.5, general trouble-shooting of hardware and some software.


In years past I taught computer K-8 and helped maintain Macs using sytems 7 and 8. Since 2001, I have not been working with computers daily, aside from doing my own work. I dabble in helping people out and enjoy the challenge of trying to figure out answers to your problems. Systems 7, 8, 9 and 10 are all in my repertoire now, at various levels of expertise. Please, NO networking questions.

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