When I faced the issue, I found that C:\Program Files\Unity\Editor\Data\Tools\VersionControl directory was not present.
When I copied C:\Program Files\PlasticSCM5\PlasticSCMPlugin.exe into that location from my downloaded install, the issue was resolved.
Unity doesn't find Plastic SCM client
in Unity 3D
Posted
A solution that worked for me.
When I faced the issue, I found that C:\Program Files\Unity\Editor\Data\Tools\VersionControl directory was not present.
When I copied C:\Program Files\PlasticSCM5\PlasticSCMPlugin.exe into that location from my downloaded install, the issue was resolved.