I'm upgrading systems from 2.3.4 to 2.3.5 using a deployment task and tagging features. I've encountered buggy issues on a number of systems (around 50). Here are some examples:
1. The MCPInstaller.x64.exe gets hung up on the system, and so does msiexec.exe. When I look at the Program Files\McAfee\MCP folder the McpService.exe and other MCP files are present, but the upgrade has not completed and system properties in EPO still show 2.3.4. Sometimes the MCP properties field is blank in EPO.
2. The upgrade succeeds and MCPService.exe 2.3.5 is present on the system, but not running. I am also seeing some of these systems fail the upgrade, and MCPService.exe 2.3.4 is still present in the MCP folder, but the service is not running on the system.
It is difficult for me to know how many more systems do not have their MCP service running when the MCP system properties are displayed in EPO, but when I look at the running services on the system using a process explorer and I find the MCPservice.exe is not actually running.
Overall I have found the 2.3.4 to 2.3.5 upgrade process fairly buggy. I have not read about any of these problems in the MCP Known issues KB, and will likely have to open a ticket and begin troubleshooting these problems with McAfee support. In the meantime, I would advise other people who are planning to upgrade from 2.3.4 to 2.3.5 to take it slow and methodically so they don't corrupt the existing MCP installation on the system.