Slowness to open the Infrastructure Manager.
IM is taking long time to open and also hang the probe GUI when you try to configure.
Even if you have resources on the hub machine like memory and CPU.
Issue related to thread locking where a hub will appear to "hang up" for 10 - 12 seconds at a time.
Deploy the latest GA robot and hub or the latest hotfixes to resolve issues related to thread locking issues.
Please use the following hotfix site to download from: