When running the AgentInstall.msi provided with agent package upgrade or agent hotfix, you get the following error:
Another version of this product is already installed. Installation of this version cannot continue.
To configure or remove the existing version of this product, use Add/Remove Programs on the Control Panel.
Agent hotfix or upgrade are provided in AgentInstall.msi package. Using the installation command:
msiexec /i AgentInstall.msi /q INSTALLDIR="C:\Program Files\Manufacturer\Endpoint Agent\" ENDPOINTSERVER="hostname" SMC="smc.hostname" KEY="" SERVICENAME="EDPA" WATCHDOGNAME="WDP" ARPSYSTEMCOMPONENT="1" will return the error.
This command is included in the install_agent.bat provided with the package.
To solve this issue use the following command instead:
msiexec /i AgentInstall.msi /q REINSTALL=ALL REINSTALLMODE=vomus
NB: This command should ONLY be used for minor upgrades and patches. This means that it can only be used to hot fix an existing agent installation that is on the same maintenance pack level. It cannot be used to upgrade to a newer maintenance pack or major version. This is because the product code used by agent builds within the same maintenance pack level all use the same MSI product code.