Fix: A required device isn’t connected or can’t be accessed

(Last updated on August 28, 2019)

We have had a few support calls where customers using Specops Deploy OS are running into trouble while PXE booting computers for installation.

The error message is as follows and it appears shortly after Windows PE starts to load.

When it fails to PXE boot, the following appears:

Windows failed to start. A recent hardware or software change might be the cause. To fix the problem:
1. Insert your Windows installation disc and restart your computer.
2. Choose your language settings, and then click “Next”.
3. Click “Repair your computer”

If you do not have this disc, contact your system administrator or computer manufacturer for assistance.

Status: 0xc0000001
Info: A required device isn’t connected or can’t be accessed.


The problem is due to Windows Update KB4489882 which enables TFTP Variable Window Extension. Microsoft recently provided a preview release of a patch, and we can confirm that the issue is completely resolved after installing this patch.

If you don’t want to install a preview patch from Microsoft, but want to partially fix the issue, use the following workaround. The fix below won’t be able to reinstall any more than 10 machines at the same time.

  1. Open a command prompt as admin and type the following command:
    wdsutil /Set-TransportServer /EnableTftpVariableWindowExtension:No
  2. Restart the WDS service.


Written by

Mikael Ingelin

Product Specialist, Specops Software

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