How-To Guides

SCCM OSD – “A required device isn’t connected or cannot be accessed”

We today ran into an issue where our SCCM OSD PXE boot was not working. It was coming up with a very confusing message stating: “A required device isn’t connected or cannot be accessed” This led us to start looking at the hard drive and the drivers, however, the solution was completely different. The problem […]

By Andrew Armstrong • 2 min read
SCCM Osd A Required Device Isnt Connected Or Cannot Be Accessed
We today ran into an issue where our SCCM OSD PXE boot was not working. It was coming up with a very confusing message stating: “A required device isn’t connected or cannot be accessed”
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This led us to start looking at the hard drive and the drivers, however, the solution was completely different. The problem was that the RamDiskTFTPBlockSize we were using on our distribution point was too high, so we had to lower it to the Microsoft default. To do this, you should follow these steps:
  • Go into regedit on your distribution point server
  • Browse to HLMSOFTWAREMicrosoftSMSDP
  • Find the RamDiskTFTPBlockSize key
  • Edit the decimal to “1456”
  • Close regedit
You should then retry your PXE boot sequence and you should find that it now works.

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Andrew Armstrong

Andrew Armstrong is a UK-based IT professional with 26+ years of hands-on experience in Windows, Windows Server, SCCM/ConfigMgr, Active Directory, PowerShell, and enterprise infrastructure.

He founded TechyGeeksHome in 2010 and has published over 1,500 practical guides covering real-world IT problems and solutions. When not solving IT problems,

Andrew develops free Windows utilities including Ultimate Settings Panel, which has been downloaded over 850,000 times.

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5 thoughts on “SCCM OSD – “A required device isn’t connected or cannot be accessed””

  1. Very nice article! This was the solution for us having problems with pxe boot on citrix virtual desktops.
    Thnak you!

  4. Very nice article! This was the solution for us having problems with pxe boot on citrix virtual desktops.
    Thnak you!

  5. Very nice article! This was the solution for us having problems with pxe boot on citrix virtual desktops.
    Thnak you!

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