Windows Update lost network share

BeeP · 10 Sep 2025 at 11:36

Hiya,

This morning my work PC had some updates to do so I rebooted and let it do its thing, all seemed ok until I tried to access and old CNC machine we have to dump a .nc file into it, apparently I can't access the network share anymore.

I can ping the machines name and IP address, I can access it from a PC which hasn't yet put on the update but just not from any that have this update.

The update is - (KB5065426) (26100.6584) I followed some online guides on group policy but so far nothing works other than simply using another pc to transfer the files over, not very convenient.

Any help is welcomed.
Cheers,
Brad/BeeP

BeeP · 10 Sep 2025 at 11:49

Fixed....ish.

I uninstalled the update, not an elegant solution but it's working.

Cheers.

Caged · 10 Sep 2025 at 12:58

Probably SMB1 related

brightside229 · 11 Sep 2025 at 09:17

Had a similar problem a bit back, remove the share/mapped drive for anything to do with this machine, run control userpasswords2 and remove any information relating to this machine from the stored account.

Restart the computer, either do \\computer name or \\ip to see if you can connect to the machine, it may ask for username and password even if password protected sharing is off, create an account and password on the machine you are trying to access hopefully this will allow you to connect.

From googling, it sounds like a security policy on the new updates that does not like you to share files with no security over your network.

Even if you turn windows updates off, it will get to a point when the machine will just download the update anyway and give you the option of "update and shutdown" or "update and restart" basically forcing you to install it

Vimes · Sunday at 18:01

This has happened to me...

Three Windows 11 machines on build 24h2.26100.4946.

Each could access each other and share. Some drives mapped etc. All access was fine with the same online MS account name and password. Even though password sharing was turned off.
It just worked.

One machine has now updated to, KB5065426, build 6584, and that machine can still access the others. It can access their shares, drives and even RDP into them. No issues.

BUT neither of the other two can access it.

Both are showing as not having the correct credentials, even though the same login, the same online MS account is being used for all three.
The Windows credentials, within Control Panel, have not changed. All three have the same admin online account.

When this update applied to one of the other machines it too went through this, I just uninstalled the update and it worked again.

I did note from searching there could be sharing issues associated with the update. I have deferred updates for a while on the working two PC's.

Not sure what to do about the one that has now updated, deleting credentials on the two that can't access it and recreating them has not helped.
I tried various group policy suggested changes, nada.

At some point deferring updates is not going to be an option, perhaps MS might fix what is wrong, or there might be an understanding of what has changed to resolve it

At times I despair with some MS updates.
Networking, for me, is, at best, akin to alchemy. MS not always helping when things go wrong or change, without feeling informed.

Rroff · Sunday at 18:20

brightside229 said:
Even if you turn windows updates off, it will get to a point when the machine will just download the update anyway and give you the option of "update and shutdown" or "update and restart" basically forcing you to install it

Windows Update Blocker so far prevents this - only approach I've found so far which 100% blocks such behaviour

otherwise sooner or later Windows will try and force it.

Vimes · Sunday at 18:22

Rroff said:
Windows Update Blocker so far prevents this - only approach I've found so far which 100% blocks such behaviour otherwise sooner or later Windows will try and force it.

Chris Titus could help there.

Caged · Sunday at 18:42

You should keep internet-connected computers with important personal data on patched, imo

Vimes · Sunday at 18:50

Caged said:
You should keep internet-connected computers with important personal data on patched, imo

That is why I do not like deferring updates.
IIRC the noted above update is classed as a security one, not a feature type. So it is needed, but I'm not sure what goes wrong with local shares and access etc.

Caged · Sunday at 18:54

I have looked after storage for CNC machines (the PC on the podium thing runs Windows 7) and the way I handle it is an isolated network with access to a NAS, then the NAS has SMB2.1 and SMB3 enabled. The CNC connects using SMB2.1, the people working and needing to put files to it use SMB3 or newer.

aaronyuri · Sunday at 19:38

Caged said:
I have looked after storage for CNC machines (the PC on the podium thing runs Windows 7) and the way I handle it is an isolated network with access to a NAS, then the NAS has SMB2.1 and SMB3 enabled. The CNC connects using SMB2.1, the people working and needing to put files to it use SMB3 or newer.

This is the same principle as a SAN except to NAS and not for block-level access. Following good practice there!

For anyone wondering if your SMB (Windows shares) security should be taken seriously, I'll refer you back to WannaCry crippling the NHS back in 2017. It used an exploit in SMB and was a self-replicating disease.

Rroff · 2025-09-23T11:49:35+0100

aaronyuri said:
For anyone wondering if your SMB (Windows shares) security should be taken seriously, I'll refer you back to WannaCry crippling the NHS back in 2017. It used an exploit in SMB and was a self-replicating disease.

Funny thing was Windows 7 got a lot of finger pointing over the incident - but it was actually SMB vulnerabilities, often involving systems on Windows 10, which enabled WannaCry.