I was trying to update QuickBooks 2005 to R10 today and it kept getting stuck in the middle of the update process.  It turns out that all I had to do fix this problem was take the QuickBooks 2005 installation CD out of the computer before installing the update.

Any users (and from reading other forums, there seems to be a lot of them) that have a problem with the update utility stopping at 24% when trying to copy the file qbupdate.exe.LOCAL might try simply removing the installation CD form the drive. Noone tells you this, but after hours of searching forums, I found the solution. Simple, yet who would have thought of it? Anyway it worked for me, and if this doesnt work, search the forums for ‘update stop’, and several other solutions are listed, but this one is the simplest, so I thought I would leave a post about it.

Source: QB update utility stops working at 24%