User profile failed to attach - WVD; ... @Nandish Mahadevappaare you running the latest version of FSLogix? Do you see a .lock file on your VHD(x) storage?
Here are other solutions for the same error: - https://www.youtube.com/watch?v=qNPGljaR_E4 - https://www.youtube.com/watch?v=GN9Ippm2gac