Q: Can't delete item from sidebar

Maybe this will help. If you monitor the "More Like This" box, other solved threads appear. Opening them usually displays other threads.

http://support.apple.com/kb/ht3728

I have a similar problem and had explained it in an ealier thread I started <https://discussions.apple.com/thread/4582326>, to which there have been no replies. In my case I am able to remove the extra (data) volume from the Favorites section, but it returns every every time any volume is mounted -- whether connecting an external disk, opening a DMG, restarting the Mac.

I can add a bit to my earlier description. I had said the problem didn't occur in a new user account. Well, after using the new account for a while, it showed up. Eventually I erased the startup volume and installed Mountain Lion (plus updates to 10.8.2) fresh. I used migration assistant to transfer only my old user, pared down applications, and network settings -- no preferences, application support stuff. The old user carried over the problem. But I immediately created a new user and have been working from it for the past two weeks, very gradually opening apps, adjusting settings, etc., and testing for the anomaly at each change. In some cases I did move preferences from a backup clone, but was always careful to test after each addition. All was well for a week, until one morning I noticed the data partition had appeared in sidebar Favorites. So I'm back to where I was. I had been documenting each change or introduction I made. The only things my notes said from the day before the sidebar anomaly appeared was launching and struggling to activate QuarkXPress 9.3, and copying over my old prefs and settings for TextWrangler. I completely removed every trace of QXP, but the problem remained. (I did not remove TextWrangler because I just can't believe it could be the culprit -- but could it?)

I really wish one of the Forum experts could offer some help.

MacBook Pro 2.5 GHz Intel Core i7 (late 2011); 8 GB memory; OS 10.8.2

Try right-clicking on the item, there should be an option "remove from sidebar"

As I wrote in my first paragraph, in my case I can remove the partiion/volume from the Favorites section (command-drag it off). But it returns absolutely every time any disk — internal or external or DMG — mounts. Why does it appear among sidebar Favorites in the first place? As the OP described, trashing com.apple.finder and com.apple.sidebarlists plists has no affect on this behavior.

I've been experiencing this problem since September.  Here's my thread.  No solution has been presented there yet, though.  Nice not to be alone now

I agree, Scotch_Brawth: it helps not to be alone. I also hope some increased activity on this thread or the one you started <https://discussions.apple.com/message/20737421#20737421> or the one I started <https://discussions.apple.com/message/20727591#20727591> will attract the attention of some of the gurus in this forum.

Did you ever try deleting ~/Library/Caches/com.apple.finder as you wondered about several months ago?

Right Click on it and Select

Remove From Sidebar

To Csound1 and anyone else who might suggest the basic method of removing an item from sidebar Favorites: I think the three of us (so far) who have this vexing problem know how to do the basic removal. At least two of us have written that we have done so and — poof! — the item does go. But, (1) the removal is temporary (2) the item returns under what would seem unrelated circumstances (when a disk mounts) and (3) the "item" in all our cases is a partition of the internal drive. Why? How could this happen? Why would a single partition of an internal drive suddenly start appearing among the sidebar Favorites, where volumes are not even supposed to be?

You really needs to read the other two threads, including my thread, more carefully, for our detailed descriptions and to see what has already been tried, albeit unsuccessfully.

Another member may have found the solution. See this thread.

—emolas

I had an unwanted item — it was just a folder on my desktop — that had insinuated itself into my sidebar. I may be stating the very obvious ('teaching my grandmother to suck eggs' as they used to say when I was a kid at school), but I got rid of it by selecting it in the sidebar, pressing Control and clicking on 'Remove from sidebar'.