Enabling insecure guest login (SMB2 / SMB3)

Since Windows 10 version 1709 (Fall Creators’ Update), there is a registry key that disables guest access on SMB2 and SMB3 called “AllowInsecureGuestAuth”. By default, this key is set to 0. Prompting users with the following message while trying to access a network share:

Solution:

1. Open the Registry editor by running the command ‘regedit’ from the run menu.
2. Browse to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\LanmanWorkstation\Parameters
3. Find the key AllowInsecureGuestAuth and change the value to 1.

or

1. Open the Local Group Policy editor
2. Go to Computer Configuration\Administrative Templates\Network\Lanman Workstation
3. For the setting, “Enable insecure guest logons” right click and choose Edit.
4. Choose “Enabled” and click OK

Relevant article: Link