Microsoft shows the current list of upgrade blocks for the May 2019 Update
Windows 10 May 2019 Update will begin to push to compatible devices in late May 2019. Windows 10 1903 is currently only available for Windows Insiders. In a recently updated blog post, Microsoft shared a list of blocked locks for Windows 10 1903.
Windows 10 May 2019 Update will be blocked from upgrading in the following situations:
- If you have an external USB device or SD memory card is attached to your PC, you will be blocked from updating to the May 2019 Update. See this support article for details. If you remove any external USB devices and/or SD memory cards, the update should proceed normally. This issue will be resolved in a future servicing update for Windows 10. For Windows Insiders, this issue is resolved in Build 18877 and later builds.
- If you have older versions of anti-cheat software used with games installed on your PC, you will be blocked from updating to the May 2019 Update. Some older versions of anti-cheat software may cause PCs to experience crashes after updating to the May 2019 Update. This block is specific to older versions of anti-cheat software. We are working with partners on getting their software updated with a fix, and most games have released patches to prevent PCs from experiencing this issue. To minimize the chance of hitting this block, please make sure you are running the latest version of your games before attempting to update the operating system.
- If you have redirected any Known Folders (for example: Desktop, Documents, Pictures), an empty folder with that same name is created in your %userprofile% directory when you update. Your Known Folders are redirected if you chose to back up your content to OneDrive using the OneDrive wizard, or if you chose to keep your content backed up during the Windows Out-of-box-Experience (OOBE). You may have also redirected your Known Folders manually through the Properties Dialog in File Explorer. This issue does not cause any user files to be deleted and a fix is in progress.
