How to Find 3rd Party Applications that Use the Mouse in my OS X Installation?

Question

I'm having a problem with Spotify that causes my mouse to not work properly. Based on my reading online, this problem is caused when third party applications like BetterTouchTool interact with Spotify. I have in the past installed such applications. I don't remember all of them, but a non-exhaustive list includes BetterTouchTool, KeyRemap4MacBook, and MagicPrefs.

I believe I have now uninstalled all such programs as I no longer use them. However, since I'm having this problem with Spotify, my gut says that one of these programs is still covertly active on my computer.

Is there a way I can get an exhaustive list of all third-party applications that might be interacting with my mouse/touchpad? I have tried obvious things like looking in my System Preferences (where such applications often have a preference set) and my Applications folder. Where else can I look?

Answer 1

This kind of software mostly works either through a helper application or a kernel extension (aka hardware driver). These usually reside in the machine /Library or your user ~/Library, not in /Applications. Check the following places:

1. User startup items: in System Preferences check the User & Groups item, Startup Items pane for helper applications which could belong to one of the softwares you described. If you think you have found the culprit, right click to get the “Show in Finder” context menu. Make an alias to the file on your desktop, then delete its startup entry in System Settings. Look for the process belonging to the item in activity Monitor an kill it there.
2. Global startup items: check /Library/StartupItems as above. If you think you have found the culprit, move the file / folder to your desktop and kill the process in Activity Monitor as above.
3. launchd items: check ~/Library/LaunchAgents, /Library/LaunchAgents and /Library/LaunchDaemons. Note that what you will find there are not the actual apps and kernel extensions, but plist files describing what launchd, the OS X service that manages startup processes, is meant to start, and how. These files are named in reverse domain name notation, i.e. tld.domain.function.plist is for function by some company whose domain is domain.tld. If you think you have found the culprit, move the plist to your desktop and reboot. I strongly suggest you do not touch anything starting with com.apple. A slightly more convenient way to do this is to use Lingon (use version 2, not the dumbed down version 3), which shows a list of all items and allows selective disabling.
4. ADDENDUM kernel extensions (thanks to @Lri who pointed out that dumb omission of mine): check /Library/Extensions and /System/Library/Extensions for possible culprits. Move to desktop and reboot. Note that last folder contains all kernel extensions needed by the operating system; do not move out anything made by Apple or belonging to any other peripheral / hardware you can identify and that is not an input device.

After each of these steps, test Spotify for erratic mouse behavior. If it persists, undo your last step (i.e. move back the plist or StartupItem and reboot / follow the alias so you can drag and top its target into the Startup Items pane). Good hunting.