I use OS X with a non-admin account, thus when ever I install and upgrade apps i'm asked for the admin username and password. Just now i'm trying to upgrade Thunderbird to version 3.0. Following these steps:
- Drag Thunderbird to /Applications it asks me to Authenticate, I press the Authenticate putton
- I get a message "An item named Thunderbird allready exists in this location. Do you want to replace it with the one you're moving". That's my old Thunderbird, which should be overwritten so I press the Replace button.
- It asks for admin username and password and I enter those.
- I get an error message "The operation can't be completed because an item with the name "Thunderbird already exists". (see item 2, i told it replace it, yet it refuses to)
- Start from again from 1.
I've had this error for a long time now, but before this Finder has always managed to overwrite the old app on the second time. This is not the end of the world as i can delete the old version and install the new one, but this has been one little annoyance for me for a long time (since 10.5.x), since something clearly is not working.