Can I filter out a corrupted user account and app as part of a migration?

Question

I am in the process of upgrading from Tiger to Leopard. I did an erase and install because of some issues with the old system, one being a corrupted user account. I am reluctant to use Migration Assistant because I don't want to bring that corrupted account over.
I have read in some other posts that if you already have a user account with a certain name in Leopard and you try to bring over one with the same same from Tiger, it will not transfer. Is this correct? If that is so I would create a user account in Leopard with the same name as the corrupted account in Tiger and that would block it, right? The next question is what constitutes the user account name, is it the designated name, often the computer name or is it the short name, often the same as the designated name but run together if it is two words. I guess I could just duplicate both names the way they appear in Tiger. Will that do it?
On a related note, is there any substantial difference between doing a simple upgrade on the one hand as opposed to an erase and install and then using migration assistant to bring everything over that way? I have a QT issue and along with the corrupted user account, I made the decision to use the erase and install option and essentially start from scratch. This, however, creates a lot of extra and perhaps unnecessary work. Would it help if I just deleted QT in Tiger so it couldn't be migrated?

Answer 1

There is a Mac OS X 10.5 help topic that answers most of your questions. Unfortunately, it doesn't seem to be available online & obviously, you can't access it on your own Mac without Leopard already being installed -- a bit of a Catch-22!
Anyway, below I have copied the text of that topic from my own Help Viewer. It lacks the formatting of the original, but I hope it will be of some use to you anyway.
*Using Migration Assistant to transfer files from another Mac*
If you need to transfer your files and important settings from an older Mac to a new one, and both computers use Mac OS X, you can use Migration Assistant.
Before using Migration Assistant, make sure you have a FireWire cable to connect the two computers.
NOTICE: If you experienced problems while using some files or applications on your old computer, you may not want to transfer those files and applications to your new computer. If you do, you may transfer corrupted data or incompatible files.
To transfer files using Migration Assistant:
1 On your new computer, open Migration Assistant, located in the Utilities folder in your Applications folder. Read the Introduction screen, and then click Continue.
2 If a dialog appears, type your password, and then click OK.
3 In the Migration Method screen, select “From another Mac,” and then click Continue.
4 Connect a FireWire cable from your new Mac to your older Mac, and then click Continue.
5 Follow the instructions in Migration Assistant to restart your older Mac and select the hard disk and user accounts from which you want to transfer. Then, select whether you want to transfer applications, files and folders, or your Library folder.
NOTE: When you first open a transferred application on your new computer, you may need to reenter the application’s serial number or registration code.
6 Select whether you want to use your old network, time zone, and sharing settings, and then click Transfer.
When Migration Assistant is finished, click Quit.
You can use Migration Assistant with a MacBook Air if both computers are connected to the same Ethernet or wireless network. See “MacBook Air: How to use Migration Assistant” at the Apple support website.