Fix 0X000008B3: Security database has not been started

Quick Answer

Open Services.msc, restart the Security Accounts Manager service (SAM), then restart the Workstation service. If that fails, reboot the machine and check DNS.

What This Error Actually Means

Your computer is trying to talk to a security database — either local (SAM) or remote (domain controller) — and it can't make the connection. In plain English: Windows can't verify who you are or what you have access to. I've seen this mostly on Windows 10 Pro and Server 2019 when someone's trying to map a drive or join a domain and the SAM service just hasn't started yet. Once had a client whose print server threw this because the SAM service was set to Manual instead of Automatic after a bad Windows update. It's not a network cable problem; it's a service chicken-and-egg situation.

The exact hex code 0X000008B3 maps to NERR_ACFNotLoaded — meaning the account file on the local machine or domain hasn't loaded. Happens a lot after a reboot when you try to log in too fast, or when the Network List Service hasn't finished initializing.

How to Fix It (Step by Step)

Open Services as admin. Hit Win+R, type services.msc, press Enter. Right-click and run as admin if needed.
Find Security Accounts Manager. Scroll down to Security Accounts Manager (SAM). Check its status — it's probably stopped or stuck starting. Right-click and hit Start. If it's already running, right-click again and Restart.
Restart Workstation service. Right below SAM, find the Workstation service (also named LanmanWorkstation). Restart it too. This service handles network logins and SMB connections.
Reboot. I know, boring. But sometimes just restarting the network services clears the cached credentials. If you can't reboot now, run this in an admin command prompt:
```
net stop workstation && net start workstation
```
That forces the SAM to reload.
Check DNS if it's a domain issue. If you're on a domain, open Command Prompt and run:
```
nslookup yourdomain.local
```
Replace with your actual domain name. If it fails, your DNS server isn't reachable — the security database might be on the domain controller. Fix DNS first.

Alternative Fixes If the Main One Fails

Reset the SAM service dependencies

Sometimes the SAM won't start because another service it depends on is missing. Open an admin command prompt and run:

sc queryex samss

Look at the DEPENDENCIES section. If you see something like RpcSs or EventLog not running, start those first. I've had to restart Remote Procedure Call (RPC) more than once.

Check the registry for corruption

This is rare but happens after botched uninstalls. Open Regedit and go to:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SamSs

Make sure the Start value is 1 (system) or 2 (automatic). If it's 4 (disabled), change it to 2 and reboot.

If you're on a domain and still stuck

Disconnect from the domain temporarily. Go to Settings > Accounts > Access work or school, disconnect the account, reboot, then rejoin. I've seen this clear up a corrupted secure channel.

Prevention Tip

Make sure the Security Accounts Manager service is set to Automatic (not Automatic Delayed Start). Also, if you're joining a domain, wait 30 seconds after boot before trying to map drives or log in with domain credentials. The SAM needs a moment to load, especially on Server 2022 with fast startup enabled.

One more thing: if you see this on a fresh Windows install, check if you've accidentally disabled the Netlogon service — that'll kill SAM too. Keep it on Automatic.