What you’re seeing
- RSAT installation stops with error 0x800F0912, reporting that the required source files could not be found.
- A retry fails with 0x800F0818 instead, indicating that the package doesn't match the Windows build on the machine.
- The admin tools install fine on internet-connected PCs but fail on offline or air-gapped workstations.
- Active Directory Users and Computers, DNS Manager and other admin consoles are still missing after the attempt.
Common causes
Every environment is different, but these are the causes our engineers find most often:
- The Features on Demand source was built for a different Windows release or build than the one installed, so the package identities don't match.
- The local source folder is missing language resources or metadata files that the RSAT capabilities depend on.
- Policy sends the machine to a WSUS server that doesn't host Features on Demand content, and direct contact with Windows Update is blocked.
- A cumulative update moved the PC to a newer build after the offline source was prepared, leaving the two out of step.
- Pending servicing operations or a damaged component store stop new Windows capabilities from being staged.
Why it matters
Without RSAT, administrators can't manage user accounts, DNS, DHCP or Group Policy from their own workstations. The usual workaround is signing in directly to domain controllers, which spreads privileged credentials onto your most sensitive servers. In regulated or air-gapped environments there is also pressure to connect a secure machine to the internet just to get the tools, which can breach the very controls the isolation exists to enforce. Every day the tools are missing, routine tasks like password resets and new-starter setup take longer.
How AskTechGurus fixes it
Skip the trial and error. A certified engineer works on your actual system, finds the root cause, and fixes it properly.
Tell us what’s happening
Submit a ticket in about two minutes. Paste the error, describe what changed, and pick your tier. No charge to submit.
A certified engineer diagnoses it
A vetted, US-based systems engineer claims your ticket, usually within minutes during business hours, and investigates over a secure remote session you can watch and end at any time.
Fixed and verified with you
The engineer resolves the root cause and confirms with you that it’s working. You don’t just get a workaround, and you get a plain-English summary of what was wrong.
Pay only when it’s resolved
Fixed price from $99, invoiced only after you approve the fix. If it isn’t resolved, you don’t pay.
Frequently asked questions
Why does this only happen on our offline machines?
Internet-connected PCs download matching RSAT packages straight from Microsoft, so a version mismatch never comes up. Offline machines rely entirely on the local source, which has to match their exact Windows build.
Is it acceptable for admins to log on to the domain controller in the meantime?
It works, but it increases the exposure of your most important servers. Getting RSAT working on the admin workstation is the better position, and an engineer can usually do that remotely.