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Is this on Windows or Mac?

Do you want to uninstall QT, or are you trying to upgrade to a newer version?
 
If you installed Qt via mpkg (versus building from source), Look for the Trolltech or Qt4.4 pkg file under /Library/Receipts/.

Under Contents, you'll find a file called Archive.bom. In the terminal, do:

lsbom Archive.bom

This will print out the list the full pathnames of all files that were installed.
 
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