Hi bethcdh,
Welcome to Microsoft Community!
Let me assist you regarding being unable to delete emails from Windows Live Mail and eventually ending up with the error code 0x800C01552.
Since you have mentioned that you have done all the troubleshooting steps that was provided by the previous moderators, I'll be asking for you to create a new user profile on your computer then try to check if you will still get the same error message.
If you are still getting the same error message, we would like to ask for you to send the fiddler trace from your computer for us to further investigate your concern. I've provided the article below on how to get the fiddler trace on your computer.
How to help the Hotmail and Outlook.com support team collect FiddlerCap traces
I've sent you a private message where you can upload the file. To view it, you need to click the notification that states “You have a private reply to this message. Click here to read it on our secure private messages section."
Note: You need to be signed in to the Microsoft Community forum to view the link. Kindly notify us here when the needed information has been provided in the private message area.
We are looking forward to your response.
Thanks,
Edmund