Something is happening at your network level.
I have seen issues like this often enough over the years, and there is a range of possible root causes.

Could be one or more of:  (been there on all of them)
 - Some failing hardware
 - a cable bent too tight (all cables have a minimum bend radius, after which stupid things happen)
 - flipping wired/wireless
 - flipping WiFi APs
 - SLP not configured correctly
 - periodic saturation of parts of the network. This can be at a packet level storm, or just a leaky microwave at just the 'right' spot.
 - bad traffic causing such a DoS

Hi Andy,

for a few days we are getting same issue on workstation login.

the error code c00000bb is combined with c00000be,

weirdest point is : this error occurs for some mapping and not all from the login script !

environment workstation and server are with nearly all latest patch's

do you known that a new oes client 24.1 exist! Try it on one workstation and see if this works!

What is the os on the workstation? do you had add smb2 and other protocols?

PascalS said:

environment workstation and server are with nearly all latest patch's

Sometimes that is the smoking gun, of a recent patch messing things up.

The challenge is to figure out which it might be.

Or it could just be those other basics I listed above 7 months ago, after all, stuff doesn't always die in a binary way and all at one instance, but all too often does a little bit at a time, like us wetware often does. Check those basics. It might just be a loose connection or a box that needs a restart.

Yes, sir, I do ;-)

Grab a copy of wireshark, and trace the network traffic. This eliminates the guesswork, and give you facts.