Issue #
When Citrix Workspace is being launched the following message is shown and the app is blocked from launching:
Online Plug-in. Please wait while Windows configures the Online Plug-in

Resolution #
This is a known issue which happens in cases when the Citrix Workspace App client installation becomes corrupt for some reason.
You will need to fully uninstall and re-install the Citrix Workspace App client: https://www.citrix.com/downloads/workspace-app/. If this does not resolve the issue, you may also need to run a series of operating system and file system integrity checks, by running the chkdsk and sfc /scannow commands in Windows. Similar commands should be run in Linux or Mac, depending on your operating system version.