KB5065426 update stops file and print sharing from working

Kevin OBrien 205 Reputation points
2025-09-10T16:09:06.4466667+00:00

I was having issues with multiple locations using windows file and print sharing with password sharing. I found windows update KB5065426 was installed and that my file and print sharing options were turned off. I also found that networks were set to public that had previously sent to private.

Even after setting the settings back, the computers would not working with file and print sharing and I had to uninstall the update to get the functionality to work.

Windows for home | Windows 11 | Windows update

27 answers

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  1. Michael Burk 50 Reputation points
    2025-09-12T08:29:21.96+00:00

    We are experiencing the same issue and the fault is definitely rooted in the SID. Two machines with the same SID can't authenticate. Our solution is to create a new Windows User, which also get's a new SID. Or reset the current user with "Sysprep".

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  2. Susan Bradley 261 Reputation points MVP
    2025-09-11T18:55:01.2833333+00:00

    https://support.microsoft.com/en-us/topic/kb5014754-certificate-based-authentication-changes-on-windows-domain-controllers-ad2c23b0-15d8-4340-a468-4d4f3b188f16

    Read that KB article.

    "In Full Enforcement mode, if a certificate fails the strong (secure) mapping criteria (see Certificate mappings), authentication will be denied."

    "If customers cannot reissue certificates with the new SID extension, we recommend that you create a manual mapping by using one of the strong mappings described above. You can do this by adding the appropriate mapping string to a users altSecurityIdentities attribute in Active Directory."

    Per my read there is no "fix" coming from Microsoft. In a domain, you need to take action.

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  3. Sidney Duffy 305 Reputation points
    2025-09-11T16:36:37.4133333+00:00

    To validate that it is the machine SID which is the root cause of failed microsoft file sharing between PCs when both computers have KB5065426 installed, I conducted the following test.

    • I made two identical virtual machines which I confirmed had the same machine SID as my desktop.
    • The first virtual machine copy was used as the reference machine and would always refuse to connect to my desktop windows share (constantly asking for username & password).
    • The second virtual machine copy as one would expect also did not connect to my desktop windows share (constantly asking for username & password). But this is expected if the machine SID is the cause.
    • On the second virtual machine copy, I then use the tool SIDCHG to change the machine SID and allowed it to reboot.
    • On the second virtual machine copy, I checked and confirmed that the machine SID had been changed and was now different to the other VM and my desktop machine SID.
    • On the second virtual machine copy, I then attempted to connect to the network share on my desktop and it worked exactly as it should :)
    • So the only thing which changed in all of this was the machine SID of the second virtual machine copy.
    • Now that I had validated this hypothesis usign some virtual machines, I found another cloned PC with same machine SID which was exhibiting the same failure to connect to my desktop windows share (constantly asking for username & password). After changing the machine SID with SIDCHG on that computer and rebooting, it could then access the network share on my desktop without constantly asking for username & password time & time again.

    Also be aware in some instances, I have also seen KB5065426 disable file & print sharing, so you may find sometimes this needs to be re-enabled.

    In a few other test I have also noticed that after KB5065426 a network can inexplicably be changed from being private to public or vice versa.

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  4. Sidney Duffy 305 Reputation points
    2025-09-11T10:52:08.7233333+00:00

    I have performed additional tests using some machines which were cloned (thus having the same machine Security Identifier (machine SID)) with and without KB5065426 applied to Windows 11 24H2.

    If KB5065426 is installed, then file or print sharing between any cloned computer with same machine Security Identifier (machine SID) - FAILS.

    If KB5065426 is uninstalled, then file or print sharing between any cloned computer with same machine Security Identifier (machine SID) - WORKS.

    If KB5065426 is installed, then file or print sharing between any computer which has different machine Security Identifier (machine SID) - WORKS.

    So it seems clear that now after decades Microsoft has killed/blocked file sharing and printer sharing due the same machine SID.

    Microsoft - wake up and fix this issue!!!!!!!!!!!!!!!!!!!!!!!!!!! or provide a way to disable the machine SID check

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  5. Giulio Gaudio 60 Reputation points
    2025-09-11T09:28:13.16+00:00

    It seems the problem appears in maior cases with Cloned OS machines using Acronis or Macrium or similar software all the PC cloned has the same SID : Security Identifier (SID) is a unique, immutable identifier of a user account, user group, or other security principal in the Windows NT family of operating systems. so after 30 years Microsoft company blocked the file sharing and printer sharing due the same SID ???!!?!

    Most companies clone operating system images to replicate them on hundreds of other machines distributed across multiple locations of the same company!!!!

    Microsoft - wake up and fix this issue!!!!!!!!!!!!!!!!!!!!!!!!!!!

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    3 people found this answer helpful.

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