If the Navigation Pane has disappeared and the Reset Layout button does not seem to fix the issue, here is the solution:
- Close Remote Desktop Manager.
- Open your File Explorer and navigate to %localappdata%, Devolutions, and then the RemoteDesktopManager folder.
- Delete the RemoteDesktopManager.ext file.
.ext File - Delete all the RemoteDesktopManagerLayout.lyt files.
.lyt Files - Open Remote Desktop Manager.