Microsoft has announced that if your PC has a USB device or SD card attached it will not be possible to upgrade the computer to the Windows 10 May 2019 Update because of an “Inappropriate drive reassignment” issue.

The Scenario

On its support site, Microsoft has announced that an attempt to upgrade a computer with the Windows 10 May 2019 Update will result in an error message being displayed if the following three factors are in place:

  1. You’re running a Windows-10 based computer that has either the April 2018 Update (Windows 10, version 1803) or the October 2018 Update (Windows 10, version 1809) installed.
  2. An external USB device or SD memory card is attached to the computer.
  3. You try to upgrade the computer to the May 2019 Update, or you have automatic updates turned on in the Windows Update settings.

Inappropriate Drive Reassignment

Microsoft says that the upgrade will not be able to occur in these situations because of the risk of inappropriate drive reassignment.  For example, a user may have booted Windows from external storage and may have left an external storage device (USB device or SD memory card) attached during the installation of the May 2019 upgrade.  Prior to the upgrade, the external device would have been mounted in the system as drive G based on the existing drive configuration, but after the upgrade, the device is reassigned a different drive letter e.g. H.  This is a situation that Microsoft is trying to avoid – hence the error message and the blocking of computers with external devices attached from receiving the upgrade.

The Workaround

According to Microsoft, the simple workaround is to remove the external media and restart the May 2019 Update installation.

Microsoft also says that the issue will be resolved in a future servicing update for Windows 10, and for Windows Insiders, the issue is resolved in build 18877 and later builds.

What Does This Mean For Your Business?

There is more than just a small element of Microsoft being cautious in issuing this error message and putting out information about the nature of the issue and workaround, after the many problems and bugs that led to Build 1809 having to be withdrawn after a few weeks before a re-issue. This time, Microsoft wants good publicity and good customer experience for its ongoing WaaS strategy.

If you’re planning to upgrade Windows 10 with the May 2019 Update and you want things to go smoothly, the advice is to make sure that you don’t have external storage devices connected to the computer at the same time.