A newer version of the product is already installed on this machine
After installing vRA 7.5 HF5, it is not possible to install any additional IAAS components - e.g. proxy agent / DEM. Attempt to launch the installer fails: Error: "A newer version of the product is already installed on this machine".
This is due to updated proxy agent launcher to version 7.5.0.16144 in HF5. "C:\Program Files (x86)\VMware\vCAC\Agents\<agent name>\VRMAgent.exe"
Since it is only the launcher - the "add remove programs" is not updated with this info.
To workaround this problem
Take a snapshot of IAAS machine
Take a backup of file "C:\Program Files (x86)\VMware\vCAC\Agents\<agent name>\VRMAgent.exe"
From VRA Appliance master node - download file:
/usr/lib/vcac/patches/repo/contents/vRA-patch/f759789753d68625f0136e9bfe159b19c4607b4cebf06566c4cf6c43fa5b4b5b/patch-vRA-7.5.9501892.12933355-HF5-Reverse/vcac/components/iaas.net/build/bin/Release/legacy/VRMAgent.exe
Stop "VMware vCloud Automation Center Agent - <agent name>" service in IAAS
Replace the VRMAgent.exe file
Install a new vSphere Agent
Replace the VRMAgent.exe with the backup file taken in step 2
Start the service
Now attempt to install DEM/Proxy agent it should work as expected