If you get the following error:

Setup failed while installing sub-component Exchange ActiveSync with error code 0xC0070643 (please consult the installation logs for a detailed description). You may cancel the installation or try the failed setup again.

startup regedit, go to HKLM/Software/Classes/Installer/Products
and browse through the Hex entries until you fine the kaseya install msxml parser - under the source list you will see a path that matches your kaseya temp directory.

backup your registry and then delete that key

you will then be able to successfully install exchange sp2 after that.

I found the info here:
http://msmvps.com/bradley/archive/2005/10/28/73370.aspx

Legacy Forum Name: Exchange Service Pack 2 install failing due to path on kaseya installed patch,
Legacy Posted By Username: expertcomp