You are upgrading your Linux Enforce server to a newer version, and at the point where the precheck begins, the upgrade fails with a message similar to the following:
"The upgrader could not detect system information. The upgrade has been canceled. Your system remains on the current version. Please see the Troubleshooting section of the Upgrade Guide for solutions."
This is caused by the user running the upgrade (typically protect) having insufficient rights to read files used during the upgrade process.
During the precheck, the upgrade process reads files in /opt/Vontu/.install4j (default location), in particular the file response.varfile, and if it fails, the upgrade will not proceed. These files are created by the installer, which is run as root, while the upgrade is run as a non-root user. On a standard system the files are created as world-readable (permission bits 644). However, if the administrator has modified the umask setting for the mount point where DLP is installed (typically /opt), the files may have lesser permissions such that the protect user cannot read them.
To resolve this problem, ensure that all files in /opt/Vontu/.install4j can be read by all users.