SMB sharing not working after windows 10 update Build 2004 update

Anonymous

Any help is appreciated

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Monkey57 3,535

Win10 20H2 fixes the issue.

Previously when 2004 broke smb1, I rolled back.

There was no registry change or any other modification made to the system. After Win10 20H2 upgrade was installed via Windows Updates; SMB1 worked as it did before the upgrade.

Thank you Microsoft.

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246 additional answers

Anonymous

2020-09-09T20:29:57+00:00

Temp Fix (encrypted smb) issue.

Context;

3 node windows server 2019 failover clustered file share, SMB 3.1.1, you can verfiy SMB version by running “Get-Smbconnection” on client.

Mapped drives via GPO.

Problem;

After Update to windows 10 2004 via endpoint manager, PC showed Mapped drives but when trying to connect we got errors, when trying to browse the unc path ‘access denied’

manually ‘net use /delete drive:’ then run gpdate resolved issue untill reboot, on a few occassion actually had to release and renew IP before the drives would connect.

Solution;

i decided to add a mapped drive via GPO to another server to rule out server issue, i mapped a SMB 3.0 share on a windows server 2012 r2, this share worked perfect on every reboot.

At this point i went back to the file share cluster and disabled file share encryption as this was the only difference apart from the SMB version and finally all my mapped drived work on reboot.

im unhappy about removing encryption in order for this to work so MS has broken something in SMB during startup of os and mapping drives.
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Anonymous

2020-09-09T07:33:41+00:00

The fix from Microsoft (KB...1744) did not solve the problem for us.

It is some kind of weird: the problem occures in the LAN. If I remove the network cable from my computer and the computer only uses WLAN during boot the problem does not occure.

Does anybody have any idea?
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Anonymous

2020-09-07T15:40:02+00:00
After updating to 2004 (knowing about the potential problem after previous experience), I put the ProviderFlags w/value 1, rebooted, and still no access.

Ran all MS updates post-2004, including a driver update for WD NAS, rebooted and still no access. Looked at my Programs and Features and somehow the box for SMBv1... was unchecked - re-checked upper level option and rebooted, still no access. The 2nd SMB option in P&F for SMB Direct was already checked. Looked in the Group Policy editor to verify setting for the Allow Guest Authentications, and it was still set to Enabled. After rebooting one more time, still no access.

Turned out, that policy enabling didn't actually set the value in my registry for it - HKLM\SYSTEM\CurrentControlSet\Services\LanmanWorkstation\Parameters\AllowInsecureGuestAuth
- to "1". Set that to 1 and my access started working again - no reboot needed.
Not sure how some of those options got turned off, could have been from my first attempt to load 2004 & get SMB to work again, but they had been turned on prior to this 2004 re-install.

So, if I had left my original SMB manipulations in place, using that ProviderFlags tip might have worked from the get go. Still ended up working, so thanks for the tip.
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Anonymous

2020-09-04T07:28:21+00:00

microsoft released a new update KB4571744 this morning that did not resolve this issue. bravo microsoft !!!
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