How to Fix Event ID 2017 and 2021 – Source Srv & Lanman
Filesharing & Network Mapping Issues with a File Server
The other day I got a call from a customer who was using a fairly decent system for file sharing in a small office of 4 people.
She told me that she was having issues connecting to the network drive where the coworkers shared their documents. This was strange because we had all the network drives mapped and they had always connected fast without issues in the past.
The server had been up and running for about a month now so I was concerned that something was going on and offered to stop in to take a look at it.
Upon inspecting the server I noted there were numerous errors in the event log referencing the following errors:
- Event ID 2017
- Event ID 2021
With sources SRV and LANMAN being referenced in some of the errors.
After referencing the error in Google I saw numerous people asking about this online and finally found an answer about what was going on and how to fix it.
It turns out this error is commonly caused by a system that is being used mainly for file sharing that has not been optimized with server settings for file sharing. It basically came down to the system not allotting enough resources to the users trying to access the server.
Now this applied even for users who were running Windows Server, Windows XP, Windows Vista or Windows 7 because the main difference between how these OS run compared to Windows Server are just registry settings that allot various resources.
So in order to resolve the problem there are two registry tweaks you need to make to optimize system resources in a PC used mainly for file sharing.
(It’s always wise to export a backup copy of your registry when you first go into Regedit before making any major changes to a system.)
01. First open Regedit. (Start > Run > Regedit)
02. Then locate the first key:
HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management\LargeSystemCache
03. By default this value is probably set to “0” and needs to be changed to “1”
04. Then locate the following key:
HKLM\SYSTEM\CurrentControlSet\Services\LanmanServer\Parameters\Size
05. By default this value is probably also “0” and needs to be changed to “3”
06. Once these changes have been made, reboot the system for the new settings to take effect.
This should resolve the errors in the event log and should clear up any issues users are having with file sharing or network mapping.
Please comment and let us know if this fixed the problem for you!












