"Failed to install the Extension Pack" for VBox 4.0 [SOLVED]

[Sasquatch]

This is probably because when you install Vbox you install it as root, but normaly it runs with user acount , so when you try to open some extension packs while loged in as user then they are automaticaly opening as user. An does not matter if you provide root password there, because Vbox was not started as root in the first place.

Not entirely true. When it asks for your administrator password or privileges, it does so to start the ExtPack install helper, which should run as admin. Usually, this works just fine, but it can happen that it doesn't. Then you have to run VB as admin itself.

[Cynyster]

I know this is an old thread. But I was having trouble installing the latest extension pack.
I am on a windows 7 Ultimate 64bit Machine.
What I was doing was Going to File>Preferences>Extentions and clicking the "add a package" button on the right (It says it as a tooltip)

That does not work!

Instead,
Right click in the white space where the extention packages would be listed. Choose Add Package from there.

I don't know why it worked one way and not the other.

Oh and the checksums Do not check out for anything on the download page... Might want to have someone look at that.

[changyuheng]

This is probably because your Windows user name contains non-English character.
Just create a new account with English alphabet then log in to install VirtualBox and Extensions.

[redneckProgrammer]

This error message is just telling you that the user you are currently logged in as is not in the admin group. You can't run the program as administrator to fix this. Just get your admin to install it for you (or you if you're the admin). If they install it under their user account (Administrator account) it will automatically be added for your user as well. Or you can have your admin add your user in the Administrator group, but I don't really recommend that nor will your administrators be very willing to do that.

[socratis]

redneckProgrammer,
Your answer is correct. However this thread was from a 2010 post!
It's beyond zombie status. It's better to let the dead rest...
Locking it.