When I login to second user account I get a blank white screen.

Question

Just updated to 10.8.3, was also having issues that seemed to be related to Spotlight and TM backups. Issues on my main user account seem to have been resolved, but I have not reactivated Spotlight or TM yet.
When I try to login to my wife's user account, it just hangs on a white screen. I've tried repairing user permissions, and also resetting PRAM and NVRAM. Disk verify checks out fine.

Answer 1

Library/Fonts:
[A hole bunch, removed to shorten post...]
Does the problem account also have a lot of fonts in the home folder? That could be the reason for a login failure. Otherwise see below.
Please read this whole message carefully, especially the warnings, before doing anything.
1. The changes to your configuration suggested here should be considered provisional; they may not solve your problem, or they may remove functionality that you find useful. If a third-party system modification that you want to keep is causing the problem, seek help from its developer.
2. WARNING: Back up all data now if you haven’t already done so. Before proceeding, you must be sure you can restore your system to its present state, even if it becomes unbootable. If you’re not sure you can do that, STOP — DON’T CHANGE ANYTHING. If you’re dissatisfied with the results of the procedure suggested below, restore from your backup. I will not be responsible for the consequences, and I will not be able to help, if you ignore this warning.
3. You should either remove or update the following system modification(s), if an update is available from the developer:
N/A
and definitely remove at least the following:
Logitech Control Center
† PeerGuardian
Hotspot Shield
† Conduit
4. Whatever you remove must be removed completely, and (unless otherwise specified in this message) the only way to do that is to use the uninstallation tool, if any, provided by the third-party developers, or to follow their instructions. If the software has been incompletely removed, you may have to re-download or even reinstall it in order to finish the job. I can't be more specific, because I don't install such things myself. Please do your own research.
Here are some general guidelines to get you started. Suppose you want to remove something called “BrickYourMac.” First, consult the product's Help menu, if there is one, for instructions. Finding none there, look on the developer's website, say www.brickyourmac.com. (That may not be the actual name of the site; if necessary, search the web for the product name.) If you don’t find anything on the website or in your search, contact the developer. While you're waiting for a response, download BrickYourMac.dmg and open it. There may be an application in there such as “Uninstall BrickYourMac.” If not, open “BrickYourMac.pkg” and look for an Uninstall button.
Again, please don't ask me to do this research for you. You can do it better than I can, because I haven't installed the product and I may not even know what it is.
If you can’t remove software in any other way, you’ll have to erase your boot volume and perform a clean reinstallation of OS X. Never install any third-party software unless you're sure you know how to uninstall it; otherwise you may create problems that are very hard to solve.
WARNING: Trying to remove complex system modifications by hunting for files by name often will not work and may make the problem worse. The same goes for "utilities" that purport to remove software.
5. I recommend that you never reinstall the modifications marked with a dagger (†) above, if any. If your problem is resolved after uninstalling all the above modifications and rebooting, but you still want to use some of those not marked with a dagger, you can experiment with putting them back, one at a time, testing carefully after each step. Keep in mind that system modifications may be incompatible with each other or with future OS X updates, so it may not be clear which one is at fault.
6. If you still have problems after making the suggested changes and rebooting, post again. Remember: if you don’t like the results of this procedure, you can undo it by restoring from the last backup you made before you started.
You installed the Conduit spyware. To remove it, back up all data, then follow the instructions on this page:
Help Center | Community Toolbar
If those instructions don't work, proceed as follows.
Triple-click the line below to select it:
~/Library/Application Support/Conduit
Copy the selected text to the Clipboard (command-C). From the Finder menu bar, select
Go ▹ Go to Folder…
Paste into the box that opens (command-V), then press return. A Finder window should open with a folder named "Conduit" selected. If it does, delete the selected item.
Repeat with this line:
/Applications/Toolbars
Now you're deleting a folder named "Toolbars". You may be prompted for your login password. Next, copy this line:
/Library
Select Go to Folder… again and paste. Don't delete the Library folder. Delete only the following items inside it, if they exist.
Application Support/Conduit
InputManagers/CTLoader
LaunchAgents/com.conduit.loader.agent.plist
ScriptingAdditions/ct_scripting.osax
Close the Finder windows you opened. Log out and log back in.