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The steps explained in the KB article is standard the process to migrate Skyline collector from MYVMware to Cloud services.
You might be unable to see the information on the wizard due to back-end data mismatch. It also takes up to 48 hours for the 'de-register' option to be available after the Skyline collector is offline.
Please provide your account details using Smartsheet Forms to help us investigate the issue in the back-end.