Such errors can often be fixed by deleting the offending dll, then repairing the component it is part of from the programs and features control panel. CoreAudioToolbox.dll is part of Apple Application Support and can normally be found in
C:\Program Files\Common Files\Apple\Apple Application Support or
C:\Program Files (x86)\Common Files\Apple\Apple Application Support.
However I've seen a similar post recently for which that hadn't helped, whereas someone else said that this approach (which is similar to one of the steps in the earlier link) had worked for them.
Remove iTunes Preference files.
Some of the files that iTunes stores settings and preferences in may be corrupt. iTunes saves its preferences in two folders. Move one of them to the desktop and test to see if the issue persists. If it does, move it back and then move the second folder. The locations for the preference folders are typically:
- C:\Users\<User>\AppData\Local\Apple Computer\iTunes
- C:\Users\<User>\AppData\Roaming\Apple Computer\iTunes
If that helps you may want to move any device backup folders into the rebuilt settings folder.
If that hasn't helped then I would suggest you go for a complete tear down of iTunes and all of its components as set out in the second box of Troubleshooting issues with iTunes for Windows updates.
The further information area has direct links to the current and recent builds in case you have problems redownloading, need to revert to an older version, or want to try the iTunes for Windows (64-bit - for older video cards) release as a workaround for performance issues, or for compatibility with QuickTime or third party software on 64-bit systems.
Review the other boxes and the list of support documents further down the page in case one of them applies.
Your library should be unaffected by these steps but there are links to backup and recovery advice elsewhere in the user tip.
If the issue persists and you have a 64-bit system try the for older video cards version which is a 64-bit installer for mostly 32-bit code, similar to all 64-bit versions of iTunes up to 12.1.
If you've tried the above without success then see the method in Install missing components. What component fails to install, and what error message does it give? See this post for steps to produce detailed logs of the installation which may reveal why iTunes won't install. Look for words like failed or error. If you get to the point where you need to do a logged install please ask and I'll provide my email address. Posting 4,500 lines of a log file here for posterity doesn't make sense.
tt2
