Windows 10 V1903: External USB storage as Upgrade blocker

[German]Users of Windows systems may experience an unpleasant surprise. Microsoft seems to block the upgrade to the Windows 10 May 2019 Update (Version 1903) as soon as external USB storage devices are found in the system. Here is some information on this topic.


Error message during upgrade

Some users who are already trying to upgrade their Windows 10 systems receive an error message during installation, saying, that the PC cannot upgrade to Windows 10 version 1903.

Windows 10 Error: What needs your attention

At the tensforum there is this thead on the topic, where it met someone in the release preview ring. The user has tried a clean install, but fails with the error. However, the answers are not very illuminating. Also the colleagues from German have received user messages here and here reporting this bug. Martin Geuß also discusses this within German site Dr. Windows.

Many guesses?

The error message from the above screenshot is not really helpful, because it does not give any indication what is going on. Martin Geuß gives the following hints at Dr. Windows.

  • When updateing a Surface, check whether a memory card is inserted and remove it. 
  • Also check if all drivers are up to date.
  • In addition, all peripherals that are not absolutely necessary should be removed.

The colleagues from are giving the following hints to overcome the upgrade issue:


  • Disconnect the machine from the Internet and attempt an offline installation using an ISO file. 
  • Uninstall programs such as iTunes, FutureMark, BattlEye Anticheat (although these cannot be the cause of the above message).

Some users identified Realtek card readers or the Creative sound card as the cause. I had also written a German blog post Windows 10 Anniversary Update: inkompatible Apps (VPC) with hints to analyze the log files to find out more details.

Microsoft explains the upgrade stopper

The colleagues from Bleeping Computer noticed that Microsoft published a support document on this topic on April 23, 2019. The article, titled This PC can't be upgraded to Windows 10" error on a computer that has a USB device or SD card attached explains the background. The Upgrade will be blocked, if you try to install Windows 10 V1903 on a computer that has a USB device or SD card attached and if the following conditions occurs:

  • You are using 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 on it. 
  • An external USB device or SD memory card is connected to the computer that you want to update.

This is simply because computers that are actually eligible for the upgrade may have a faulty drive reassignment on the external USB media during the installation of the Windows 10 May 2019 Update.

For example, if you try to upgrade to Windows 10 May 2019 Update on a computer that has the October 2018 update installed and a USB stick plugged into a USB port, it may fail. Before the upgrade, the USB stick would have been mounted as drive G due to the existing configuration. After the upgrade, however, the device will be assigned a different drive letter. For example, the USB stick with the drive letter H will be reassigned. But this leads to issues.

Therefore Microsoft blocks Windows 10 May 2019 Update installation on such machines with the error message discussed above.

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2 Responses to Windows 10 V1903: External USB storage as Upgrade blocker

  1. F.G. says:

    Build 18362.145 is supposed to fix the problem, but unfortunately the windows installer has not been fixed and it is blocking the upgrade on machines that have USB drives plugged in even if upgrading to build 18362.145 or reinstalling on a machine that is already at the build level.
    Note that not all types of USB flash drives have been blocked, but the most common ones are. I tried with different USB drives and some are blocked while other ones elude the block and allow the upgrade. MS needs to fix the windows installer and remove the block by creating a new Windows.iso with all the fixes required.
    Also upgrading from a Windows.iso located on an external USB HDD worked fine, it seems that the block is only applied to specific thumb drives.

    • guenni says:

      Thanks for your feedback – you confirms my doubts. Maybe Microsoft decide to update the install images created via Media Creation Tool (MCT) or offer a fix via dynamic updates, that will be downloaded during install.

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