You would like to show your appreciation for our help . Gladly. 🙏 We thank you for your donation!

Freely available Apt-Repository
GITLAB:

So you can control the state of the service as well as the QGA VSS provider. What I would do is: uninstall every QEMU-GA form AddRemovePrograms. look if c:\Program Files\qemu-ga\qemu-ga.exe is still there (shouldn't be in C:\Program Files (x86)) if not, copy the entire c:\Program Files\qemu-ga\ folder from an existing server to this server run

"c:\Program Files\qemu-ga\qemu-ga.exe" -s uninstall
"c:\Program Files\qemu-ga\qemu-ga.exe" -s vss-uninstall

install QEMU-GA again from the right MSI file If after this you are still left with the issue you can try and get some output from the command the MSI is trying to run:

"c:\Program Files\qemu-ga\qemu-ga.exe" -s vss-install

Source: https://forum.proxmox.com/threads/qemu-guest-agent-installation-issue.43006/