Agent upgrade failed. The process cannot access the file \\DCName\slagent\slagentsvc.dll because it is being used by another process. (4237652)

When upgrading Active Administrator agents, the following error is displayed:

 The process cannot access the file \\DCName\slagent\slagentsvc.dll because it is being used by another process.

Rename the dll:

1. On the DC that the agent will not upgrade, open the path: C:\Windows\slagent
2. Rename slagentsvc.dll to slagentsvc.dll.old
3. Try upgrading the agent again

If the issue persists please try uninstalling the agents and reinstall them:

1. Open the Active Administrator console
2. Expand Auditing & Alerting
3. Select Agents
4. Highlight all of the domain controllers, right click and select Remove
5. Once removed, click the Install button and select the domain controllers to reinstall the agents