We can no longer be installed as non-admin user from WSS Agent 7.1+ for Windows.
If you install WSS Agent 7.1+ as a non-admin user, the following message will be displayed.
Release :7.1 +
Component :WSS Agent
This has actually always been the intended behavior ,but due to a bug in a third party library, it was not being enforced in previous versions of WSS Agent.
[Workaround]
If you want to install as non-admin user, please run with CLI.
This is a specification of Windows.
1. Right click the command prompt and choose ‘Run as Administrator’
2. In the command prompt, input msiecec -i \Path\To\wssa-installer.msi
Example: msiexec -i C:\downloads\WinWSSAgentInstaller64-7.1.1.14315.msi
3. Press Enter to start the install process.