A Note About Agent Version 4.6.11
Retrace Agent v126.96.36.199 shipped with a new executable packaged (EnvCleaner.exe) that would, upon uninstall of the agent, remove environment variables set for profiling functions. It would also be triggered during an upgrade to later versions.
Inadvertently, this executable was compiled against .Net 4.5.2 without that version of the .Net Framework being a prerequisite for the installer.
Because it would only be executed on uninstall / upgrade, this allowed the install to succeed, and only manifests later during that uninstall or upgrade, causing the action to fail if .Net 4.5.2 is not on the machine.
We have made available a new version, compiled against .Net 4.5. Download here and extract into the Retrace install folder [Program Files (x86) path]\Stackify and then perform your uninstall or upgrade.