Internal Errors 2503 and 2502?

Check the NTFS security on the %systemroot%\WINDOWS\Installer folder Browse to C:\Windows\Installer and right click it Properties go to the Security Tab It should at least have the following perms set:

Administrators Full Control
System Full Control
Users Read& Execute.

Something, probably malware, hosed my security on the folder and removed the Administrators and Users perms. Once I gave it the above perms the installer msi packages started working again.

Also check the Registry permsions for the HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Installer

They should be set similar.

Hello, I am also getting "Internal error 2502". It occurs about 3/4 of the way through installing Microsoft Office. The error message pops up briefly, then my computer shuts off. I followed your instructions but when I try to change the permissions, the little check boxes under "Allow" and "Deny" are grayed out, preventing me changing the settings. Any suggestions? Thanks!

Hi, I cant seem to install or uninstall anything either, and I get those same error codes, 2502 and 2503. I have Vista 64 bit but no Installer folder in c:windows. Also, how does one go about checking 'registry permissions'? Let me just put this out there, we did not all major in Computer Science ok, how about showing some compassion for those who need some step by step instructions. Any help would be greatly appreciated.