Windows 11 KB5101650 Fails to Install with Inaccessible Boot Device (0x7B)

Hello everyone,

Windows Update keeps attempting to install a security update, but the system fails to boot during the process.

Problem
Windows Update tries to install 2026-07 Security Update (KB5101650) (26200.8875), but it consistently fails with the following error:

Inaccessible Boot Device 0x7B

Click to expand...

System Details
- OS: Windows 11 Home
- Version: 25H2
- OS Build: 26200.8655
- Motherboard: MSI Z490 motherboard

What Happens
- Windows Update downloads and attempts to apply the update.
- On reboot, the system throws the 0x7B Inaccessible Boot Device error.
- Automatic Repair triggers, successfully undoes the changes, and the PC restarts back into Windows.

How can I resolve this issue so the update can complete successfully?

Thanks everyone.

I would hide (block) the specific update using Microsoft Windows Update Show/Hide Tool or Windows Automatic Updates Manager (WAU Manager). These tools search for available updates and show you a list. Just check the box of the specific update you want to hide (block) and proceed. Both are available from Major Geeks:


PS: Microsoft no longer provides the Tool in their site but when they did they claimed it was for old Windows versions up to v1809 and doesn't work in newer versions. That's not true, I have successfully used it in all Windows 10 versions up to 22H2 and all Windows 11 versions. Yes, there might be some computers that it doesn't load (rare), but in that case use WAU Manager instead.

spapakons said:

I would hide (block) the specific update using Microsoft Windows Update Show/Hide Tool or Windows Automatic Updates Manager (WAU Manager).

Click to expand...

How does that help getting the update installed?

@TerryG

Try installing KB5121767 instead of KB5101650.

KB5121767 replaces KB5101650.

KevTech said:

How does that help getting the update installed?

@TerryG

Try installing KB5121767 instead of KB5101650.

KB5121767 replaces KB5101650.

July 18, 2026—KB5121767 (OS Builds 26200.8894 and 26100.8894) Out-of-band | Microsoft Support

July 18, 2026—KB5121767 (OS Builds 26200.8894 and 26100.8894) Out-of-band

support.microsoft.com

Click to expand...

It doesn't help to get it installed. It helps to prevent it from getting installed until a new update renders it obsolete. So I would block the problematic update to avoid issues and eventually install a newer update that hopefully will not have issues which will include the functionality of the problematic update. That's the plan. In the meantime if there's a workaround to avoid the issues, I would run the tool again and unhide (unblock) the update and let it install. I did that with the cumulative update for build 8117 so I could stay on build 8037 until I found the way to fix the issue it caused (unable to load Classic Explorer Bar from Open Shell).

Great replies from both. I will definitely block the KB5101650 and attempt the KB5121767.

Thanks, everyone. Super help.