Why does GarageBand audio work for guest user but not my account?

Question

Hello, I have a 15-inch MacBook Pro (2.2 GHz Intel Core i7, 4GB 1333 MHz DDR3) from late 2011 that I bought brand new in 2012. I'm running OS X Mavericks 10.9.4 and my MacBook has 500 GB of storage.
About a month or two ago I tried to download the new GarageBand (10.0.2) but I had trouble completing the loops download. The download would stop halfway through because of a network error. So last week I decided to try to download it again, and I was able to do so after reading some discussions about the issue. I successfully completed the download in safety mode and then I restarted my MacBook. At this point I was able to open GarageBand 10.0.2 and create a new project. Unfortunately, there was no audio coming through the output and sound bar for the various audio components in GarageBand. I had no audio when previewing the loops or playing it back in an audio track. I didn't really test anything else out because I figured I needed to fix this problem first. I have read many discussion boards about audio problems with GarageBand. I have already made sure everything is set properly in the GarageBand preferences and the audio preferences in system preferences. I've tried restarting GarageBand and restarting the computer.
This evening I found a discussion from the username icewhatice and they seemed to have had my exact problem. I'm not sure that I found the answer on this discussion though. For reference, this is what icewhatice posted: "I have no audio coming from Garageband 10.0.2. Downloaded it on Saturday and have spent the last two days trying to figure out why it won't work. I'm using a macbook pro with an Alesis QX49. GB registers keyboard when I plug it in but no sound whatsoever, not even from the onscreen keyboard. It seems to read the keyboard as if I play a C chord, it appears in the display. I've done all the obvious stuff like check preferences, restart, I've deleted and downloaded new GB several times and always with same result. Actually, it took me about four attempts to download it in the first place as I was getting an internet connection error message right at the end of the download, and I see others have had that problem. Managed to solve that by downloading in safe mode but now the no sound thing is driving me absolutely crazy because I can't play my keyboard!!!!! Also, worth noting that there is no audio level being read anywhere, I believe in the new version this appears in the volume control at the top. I've also looked into it potentially being a problem with my keyboard and it possibly needing an update but can't find any difinitive answer for that anywhere. I've stopped looking into that because the on screen keyboard doesn't even work - if that worked then I would know at least GB works and it's something to do with the keyboard. So, I am at a complete loss. If anyone has any ideas about why this is happening or what I could do to solve then I would be very grateful."
After reading this, I realized that I am unable to create new tracks, and I realized that I have the same problems with old projects saved from the last version of GarageBand I had. I have not tried to download GarageBand again since it did not work for icewhatice. léonie ended this post by saying: "Something is certainly wrong - either the current project, some settings in your user account, or the downloaded GarageBand version. Or incompatible software may be interfering. If a new project does not work, try to test by logging into a different user account, for example the "Guest User" account. Create a new project using this account. Does GarageBand work better from this account?  Then we will need to troubleshoot your preferences."
I have tried this and started a new GarageBand project in the "Guest User" account. GarageBand was working fine in the "Guest User" account and all of the audio was working properly. Does anyone know how I should troubleshoot my preferences?

Answer 1

If an application is working in a different account, but not in your regular account,try t find out, what you configured differently in your own account, for example start-up items or preference panes you are using, applications and other helper tools, that are only installed for your regular account. As a first guess, remove GarageBands preference files from the user library in your Home folder.
But you will have to reset all settings you did in the GarageBand preferences dialog. And GarageBand will not remember the last project. You'll have to find the file manually.
Remove these files from your User Library to a folder on your Desktop:
~/Library/Containers/com.apple.garageband10/
~/Library/Preferences/com.apple.garageband.plist
~/Library/Caches/garageband
Quit GarageBand, then remove the files to a folder on the Desktop and restart the computer, before trying again to open GarageBand.
You user library may still be hidden, as is the default in Mavericks: To open your hidden user library:
Select the "Home" folder icon (the little house)  in the Finder's sidebar and press the key combination ⌘J to open the "view options".
Enable "Show Library Folder".
Then open the Home folder and open the Library folder inside and navigate to the Preferences, Caches, or Containers folder. Remove these folders completely - don't leave anything inside:  ~/Library/Containers/com.apple.garageband10/,
~/Library/Caches/garageband  .