I'm having a problem running Windows Sandbox on my Windows 11 PC. When I start Windows Sandbox, it stalls at the logo for ten minutes or so, and then an error message shows up: Restarting the PC and uninstalling and reinstalling Windows Sandbox don't correct the problem. Anybody else experiencing this problem?

Error in Windows Sandbox, Windows version win11 25h2 26200.7462 error (0x800705B4) timeout I have tried uninstalling and installing the Windows Sandbox feature and I get the same error. I have tried deleting the registry key: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Containers\CmService then uninstalling Windows Sandbox, restarting, and then reinstalling to regenerate all the files, and the result is the same error. The problem or bug lies in the fact that when Windows Sandbox runs, in the directory C:\ProgramData\Microsoft\Windows\Containers\ContainerStorages, a folder is generated containing files created by the executable WindowsSandboxServer.exe, specifically sandbox.vhdx and .vmgs. Generally, these files don't usually occupy more than 200 megabytes, but since the Windows 11 December system update was installed, the files being generated can reach more than 1 gigabyte. When they reach that size, the WindowsSandboxServer.exe process shuts down automatically, I assume due to some kind of bug or timeout the files that were being generated (which are the base of the Windows Sandbox) disappear due to the aforementioned bug or process timeout, and that is when the WindowsSandboxRemoteSession process shows you the error: Could not initialize Windows Sandbox. This operation returned because the timeout period expired. (0x800705B4) It is clear that this is a bug. I should mention that the Windows Sandbox application is updated from the Microsoft Store. Best regards,

Guys, I've found a solution: Open Settings > System > Recovery. Click Reinstall now if you see Fix problems using Windows Update . Check the Automatically restart my PC 15 minutes after installation box and click OK . Windows Update will check for updates and install the repair version of the latest Windows 11 version. When you see the It's nearly time to restart dialog box, click Restart now . After Windows 11 has been repaired by using Windows Update, try starting Windows Sandbox. If a solution works, notify me.

I have exactly the same problem on 20 machines please fix this ASAP ( i tried everything, in my case nothing worked) . Thanks

Still not working on Windows 11 build 26200.7462.

Please address this long-standing issue with Windows Sandbox - Windows Sandbox fails to open with 0x800705B4*. Best regards,*

Windows Sandbox fails to open with 0x800705B4

Michael Higham 265

I'm having a problem running Windows Sandbox on my Windows 11 PC.

When I start Windows Sandbox, it stalls at the logo for ten minutes or so, and then an error message shows up:

User's image

Restarting the PC and uninstalling and reinstalling Windows Sandbox don't correct the problem.

Anybody else experiencing this problem?

David Elliott 30 Reputation points

2025-12-12T11:37:46.44+00:00

Same here with Windows Sandbox not starting with (0.800705B4).

Windows Sandbox is turned on in "turn Windows features on & off."

Sandbox opened and worked normally previously but I am unsure if I tested this after update KB5070311. But it definitly does not work after KB5072033.
JM 65 Reputation points

2025-12-12T15:36:55.9266667+00:00

I have the exact same issue, and going to Windows Store just says Windows Sandbox is installed (there is no update pending for it)

Win 11 Build 26100.7462
daniel grandjean 0 Reputation points

2025-12-15T10:32:37.82+00:00

Not yet install KB5072033 and already not working.
Krzysztof Huryn 30 Reputation points

2025-12-19T09:31:58.7133333+00:00

Exactly the same issue here, since a week or so ago.
Windows 11 Pro 25H2 (OS Build 2600.7462).
Tried all the obvious steps including removing/re-adding the Sandbox feature.
Tried starting Sandbox with both standard settings and using my own .wsb with the <vGPU>Disable</vGPU> added. None of the methods work.
When activating Sandox, generation of the temp files in c:\ProgramData\Microsoft\Windows\Containers\ContainerStorages\ takes some minutes while the folder grows to just below 2 GB, then the (0x800705B4) error appears.
micTronic 0 Reputation points

2025-12-29T11:52:56.12+00:00

See the issue also reported here:
https://github.com/microsoft/Windows-Sandbox/issues/101
Bijan 0 Reputation points

2026-02-11T07:54:58.2966667+00:00

I noticed this problem in January. Tried updating to build 26200.7628 and reinstalling the sandbox. However, the issue still persists with a few minutes of loading—then the sandbox crashes with 0x800705B4.
CharlyArg 0 Reputation points

2026-05-10T20:04:56.6166667+00:00

Chiming in here as I have 22600.8246 and still having issues to start Sandbox in Windows 11. Oddly enough I found out that if I start it just as soon as I login, it will work; thus: application. In my case it was Moto's Smart Connect application (it connects to your smartphone). But worth it to check the ones open.

29 answers

rhadamantys 70 Reputation points

2025-12-15T12:02:05.6266667+00:00

Error in Windows Sandbox, Windows version win11 25h2 26200.7462 error (0x800705B4) timeout

I have tried uninstalling and installing the Windows Sandbox feature and I get the same error.

I have tried deleting the registry key:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Containers\CmService

then uninstalling Windows Sandbox, restarting, and then reinstalling to regenerate all the files, and the result is the same error.

The problem or bug lies in the fact that when Windows Sandbox runs, in the directory C:\ProgramData\Microsoft\Windows\Containers\ContainerStorages, a folder is generated containing files created by the executable WindowsSandboxServer.exe, specifically sandbox.vhdx and .vmgs.

Generally, these files don't usually occupy more than 200 megabytes, but since the Windows 11 December system update was installed, the files being generated can reach more than 1 gigabyte.

When they reach that size, the WindowsSandboxServer.exe process shuts down automatically, I assume due to some kind of bug or timeout the files that were being generated (which are the base of the Windows Sandbox) disappear due to the aforementioned bug or process timeout,

and that is when the WindowsSandboxRemoteSession process shows you the error:

Could not initialize Windows Sandbox.

This operation returned because the timeout period expired. (0x800705B4)

It is clear that this is a bug. I should mention that the Windows Sandbox application is updated from the Microsoft Store.

Best regards,
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Michael Higham 265 Reputation points

2025-12-24T20:26:13.2266667+00:00
Guys, I've found a solution:
1. Open Settings > System > Recovery.
2. Click Reinstall now if you see Fix problems using Windows Update.
3. Check the Automatically restart my PC 15 minutes after installation box and click OK.
4. Windows Update will check for updates and install the repair version of the latest Windows 11 version.
5. When you see the It's nearly time to restart dialog box, click Restart now.
6. After Windows 11 has been repaired by using Windows Update, try starting Windows Sandbox.
If a solution works, notify me.
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3 people found this answer helpful.
Howard Rimmer 0 Reputation points

2025-12-25T14:17:53.27+00:00

Fantastic it worked, after performing all the suggested solutions this one did the Job. It took quit a time on a i9 14900k, 64g 2tb Nvme but well satisfied thank you will do it after Xmas on my other PCs that had the same error.

Krzysztof Huryn 30 Reputation points

2025-12-26T13:25:31.57+00:00

Sadly, reinstalling 25H2 did not solve the issue for me. I have exactly the same symptoms as before the reinstallation (after attempting to start Sandbox, there is a long wait, then the 0x800705B4 error shows).

It is quite clear that version 25H2 broke the Sandbox.

I would very much like to see a comment from a Microsoft employee regarding this issue. But maybe they do not read this.

Vladimír Kordas 10 Reputation points

2025-12-26T13:35:04.68+00:00

I tried that too and it didn't help me either.

JM 65 Reputation points

2025-12-29T17:37:02.07+00:00

Worked for me! Thanks!
I have rebooted since as well and Sandbox still working.
It took quite a while to complete but sorting the issues was worth the wait.

Stéphane Barrois 5 Reputation points

2025-12-29T23:02:28.39+00:00

Hi,
"If a solution works, notify me."
I "notify" that is not working for me. I still have a 0x800705B4 error after a "Fix problems using Windows Update."

Guillermo Lozano 5 Reputation points

2025-12-31T03:55:57.52+00:00

Hi,

This worked for me.

Eric Garnier 6 Reputation points

2026-01-05T08:14:33.3+00:00

Does not work for me.
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Giacomo.Angelini 15 Reputation points

2025-12-16T14:33:09.1233333+00:00

I have exactly the same problem on 20 machines please fix this ASAP ( i tried everything, in my case nothing worked) .

Thanks
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Howard Rimmer 0 Reputation points

2025-12-17T14:59:39.0533333+00:00

Agreed this problem exists on my 5 PC and laptops all running the latest updates that are recommended, I have tried every fix and to no success very very frustrating. retired IT guy with 30yrs in the game.
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Michael Higham 265 Reputation points

2025-12-09T18:46:54.1633333+00:00

Still not working on Windows 11 build 26200.7462.
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Roland Ambrosi 5 Reputation points

2025-12-12T19:32:10.04+00:00

I also have the problem with build 26200.7462.

Reinstall sandbox feature an repair installation of Windows 11 does not fix the problem.
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Stefan 10 Reputation points

2025-12-19T08:12:03.65+00:00

Please address this long-standing issue with Windows Sandbox - Windows Sandbox fails to open with 0x800705B4*. Best regards,*
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Windows Sandbox fails to open with 0x800705B4

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