Groups Users/Administrators file permissions problem

Hi,

I have one account which is member of Administrators and HomeUsers groups.
When I set file permissions to Deny Read for Users group, above mentioned account cannot read the file.
What is the reason? Above mentioned account is not a member of Users group and this setting should not affect this user.

Thanks for an answer

Every local user is member of the "users" group, even if not explicitly listed in its group membership options. So yes, this entry effectively affects him. Also, take into account that "deny" takes precedence over "allow", so denying him in any entry results in an access denied, even if other entries give him access.