There have been some bugs and issues with Microsoft’s Windows 10 May Update/1903 feature update since Microsoft kicked off its rollout in late May. But the 1903 complaint I’ve gotten most often (so far) is from users who want to install the update but can’t and don’t know why.
Microsoft has added a new notification which some users whose devices aren’t ready or able to install the update are seeing when they attempt to proactively grab the 1903 release. As originally noted last week by Windows Latest, Microsoft has added a new message to its Windows Update page.