Just tried to install Java 1.6 Update 19 on a corporate Windows 7 Enterprise Machine and the installation failed with the following message:
Data1.cab has an invalid digital signature (Error 266 returned by WinVerifyTrust)
To cut a long story short: The problem was that the file couldn’t be verified because it was signed with a new certificate by Sun. This new certificate depends on a new VeriSign certificate (Root Authority Certificate) that is by default not included in Windows 7.
Normally Windows updated its list of Root Certificates automatically, but this does not work in this environment since all Internet Connections are blocked.
The solution is rather simple: Download the update file manually from
and install this file with the “/Q” switch (no reboot required).
Now Windows has a current set of Root Certificates and the installation of Java will work.
For some more information, see Microsoft KB931125.