Important: Windows KB5083769 update may cause backups to get stuck

[YasarYY]

Also tested with core isolation features on and off, and all backup types work fine all the time.
FWIW, executing "vssadmin list writers" from an elevated prompt never returns, independent of core isolation features being on or off.

Could you please provide the output of the "vssadmin list writers" command? Thanks.

C:\Users\Yasar>vssadmin list writers
vssadmin 1.1 - Volume Shadow Copy Service administrative command-line tool
© Copyright 2001-2013 Microsoft Corp.

Waiting for responses.
These may be delayed if a shadow copy is being prepared.

("Waiting for responses" lines come after 10 seconds, output stays like this for at least 20 minutes. I didn't keep the command window open more than that.)

[admin]

Could you please provide the output of the "vssadmin list writers" command? Thanks.

C:\Users\Yasar>vssadmin list writers
vssadmin 1.1 - Volume Shadow Copy Service administrative command-line tool
© Copyright 2001-2013 Microsoft Corp.

Waiting for responses.
These may be delayed if a shadow copy is being prepared.

("Waiting for responses" lines come after 10 seconds, output stays like this for at least 20 minutes. I didn't keep the command window open more than that.)

Thanks. It seems that there is no useful information, making it impossible to determine which VSS writer is not working properly.

[YasarYY]

A bit of side note; for "Waiting for responses" issue, people say at some forum pages (i.e. [1]) that installing optional Windows 11 update KB5083631 [2] solves that for some users.

I went and installed that optional update, and "vssadmin list writers" really returned a list. After a couple of minutes, and before I reinstall the last official HBS to try, I rerun the command and it unfortunately stuck at "Waiting for responses" again.

So, it just temporarily make the listing work for a short time. Possibly by a similar effect as previously written "stop services/clean/start services" suggestion.

[1]: https://www.reddit.com/r/MSP360/comments...aking_vss/

Untitled
.theme-light,:root{--rem360:22.5rem;--rem320:20rem;--rem192:12rem;--rem144:9rem;--r…

[2]: https://support.microsoft.com/en-us/topi...e66c97d759

April 30, 2026—KB5083631 (OS Builds 26200.8328 and 26100.8328) Preview - …
Related topics × Windows 11, version 26H1 Windows 11, version 26H1 April 30, …

[Bespoken]

A bit of side note; for "Waiting for responses" issue, people say at some forum pages (i.e. [1]) that installing optional Windows 11 update KB5083631 [2] solves that for some users.

That KB preview did not change anything for me. A reboot allows vssadmin to complete, but that only lasts for about 10 minutes.

[al3x]

Would be interesting to see the output of vssadmin list writers during that first 10 minutes after a restart then. Maybe there’s something strange in that list that gives a hint.

Could also be that something new gets injected after that time of course, but you‘ve got to start somewhere.

[Bespoken]

*** run right after reboot - all normal ***
C:\Windows\System32>vssadmin list writers
vssadmin 1.1 - Volume Shadow Copy Service administrative command-line tool
© Copyright 2001-2013 Microsoft Corp.

Writer name: 'Task Scheduler Writer'
Writer Id: {d61d61c8-d73a-4eee-8cdd-f6f9786b7124}
Writer Instance Id: {1bddd48e-5052-49db-9b07-b96f96727e6b}
State: [1] Stable
Last error: No error

Writer name: 'VSS Metadata Store Writer'
Writer Id: {75dfb225-e2e4-4d39-9ac9-ffaff65ddf06}
Writer Instance Id: {088e7a7d-09a8-4cc6-a609-ad90e75ddc93}
State: [1] Stable
Last error: No error

Writer name: 'Performance Counters Writer'
Writer Id: {0bada1de-01a9-4625-8278-69e735f39dd2}
Writer Instance Id: {f0086dda-9efc-47c5-8eb6-a944c3d09381}
State: [1] Stable
Last error: No error

Writer name: 'System Writer'
Writer Id: {e8132975-6f93-4464-a53e-1050253ae220}
Writer Instance Id: {294575f2-b1b4-42a3-8c83-3669326671ef}
State: [1] Stable
Last error: No error

Writer name: 'ASR Writer'
Writer Id: {be000cbe-11fe-4426-9c58-531aa6355fc4}
Writer Instance Id: {302af37e-6d59-406e-97d5-5573a7722c4f}
State: [1] Stable
Last error: No error

Writer name: 'Shadow Copy Optimization Writer'
Writer Id: {4dc3bdd4-ab48-4d07-adb0-3bee2926fd7f}
Writer Instance Id: {8cd48279-b54b-43c6-aaf7-1c3c92606ece}
State: [1] Stable
Last error: No error

Writer name: 'Registry Writer'
Writer Id: {afbab4a2-367d-4d15-a586-71dbb18f8485}
Writer Instance Id: {6a943fc3-9e74-4117-8fd4-74a0c149efa9}
State: [1] Stable
Last error: No error

Writer name: 'WMI Writer'
Writer Id: {a6ad56c2-b509-4e6c-bb19-49d8f43532f0}
Writer Instance Id: {f8a7332d-2aef-4c6f-9979-3602aebde61b}
State: [1] Stable
Last error: No error

Writer name: 'COM+ REGDB Writer'
Writer Id: {542da469-d3e1-473c-9f4f-7847f01fc64f}
Writer Instance Id: {1bc8629c-4178-4970-9a36-4719e312aa59}
State: [1] Stable
Last error: No error

Writer name: 'MSSearch Service Writer'
Writer Id: {cd3f2362-8bef-46c7-9181-d62844cdc0b2}
Writer Instance Id: {d7a49259-c710-445e-9cd2-68fbfb89caef}
State: [1] Stable
Last error: No error

[al3x]

*** run right after reboot - all normal ***
C:\Windows\System32>vssadmin list writers
[...]
Writer name: 'Task Scheduler Writer'
Writer name: 'VSS Metadata Store Writer'
Writer name: 'Performance Counters Writer'
Writer name: 'System Writer'
Writer name: 'ASR Writer'
Writer name: 'Shadow Copy Optimization Writer'
Writer name: 'Registry Writer'
Writer name: 'WMI Writer'
Writer name: 'COM+ REGDB Writer'
Writer name: 'MSSearch Service Writer'

There's one writer missing in that list that I can see on all of my machines:

Writer name: 'BITS Writer'
Writer Id: {4969d978-be47-48b0-b100-f328f07ac1e0}

This might be a long shot but I also found something about the BITS writer and KB5083769:
https://learn.microsoft.com/en-us/answer...download-t

Possible issue with KB5083769: BITS/SOAP download timeouts and bitsadmin freeze …
I would like to report a potential issue related to the April 2026 cumulative updat…

Additionally, during the failure state, we observe that the following command becomes unresponsive (appears to freeze):
bitsadmin /list /allusers

Could this have something to do with it? Can you recheck if that command also fails for you after those 10 mins?

Normally that BITS writer should be inserted automatically as soon as the "Background Intelligent Transfer Service" service is started, maybe that service isn't started on your machine.
Or it might require a repair. Unfortunately I didn't find a good guide for repairing the BITS service so far. There's one guide here, but it doesn't seem to work correctly, just tested this in a VM. But anyway, that's also just a wild guess.

Issues with BITS | Microsoft Docs
Zu Hauptinhalt wechseln Zur Ask Learn-Chaterfahrung wechseln Dieser Browser wird ni…

Nevertheless, this still needs to be investigated by Microsoft...

[Bespoken]

There's one writer missing in that list that I can see on all of my machines:

Writer name: 'BITS Writer'
Writer Id: {4969d978-be47-48b0-b100-f328f07ac1e0}

BITS Writer does not show up for any of the 3 PC's that I have checked. They are all running Win 11 Home 25H2, and in Services BITS is Running Automatic (Delayed). Two of those PC's perform backups fine, but the 3rd either requires a reboot then run backup (or use of the temporary version).

[lavande]

Microsoft can be very responsive in releasing KB out of band. To do this, the problem needs to be reported via feedback.

In Windows 10 and 11, Microsoft recommends using third-party backup software because the built-in backup is no longer updated. And if this were to change, I don't think Microsoft would block third-party software. For example, antivirus programs can take over from Windows Defender.

[Bespoken]

Just installed the latest MS 2nd Tuesday Security Update KB5089549, and reinstalled the original HBS V5.8.2.0. Successfully performed as full System Backup. Yeah! "VSSadmin list writers" successfully completed after reboot, 15 minutes later, and after the backup.

It seems that MS have fixed the VSS problem, but will continue to monitor its status over the next few days.