If the AD FS plugin was installed correctly, you can find the LastPassAttributeStore listed.

1. On your AD FS server, open the AD FS Server Manager tool.
2. Go to AD FS > Service > Attribute Stores.
3. Check if LastPassAttributeStore is listed.
   
   Warning: If you cannot find the Attribute Store, it means that the installation failed. Reinstall the AD FS plugin, and confirm that the name of the custom attribute value and the version are both correct.
4. Uninstall the LastPassAttributeStore.msi.
5. Log in with your email address and master password to access the Admin Console at https://admin.lastpass.com/.
6. Go to Users > Federated login.
7. Confirm that the name of the custom attribute value is correct.
8. In the "LastPass Custom Attribute Store" section at the bottom of the page, click either Download for ADFS Server 3.0(For Windows Server 2012 R2) or Download for ADFS Server 4.0 (for Windows Server 2016) and save the LastPass CustomAttributeStore.msi file.
9. Log in to your primary Active Directory Federation Services (AD FS) server, then transfer the CustomAttributeStore.msi file onto the desktop of your AD FS server and double-click it to run it.
10. Click Next.
11. Enter your LastPass Business Service Provider URL, then enter your custom attribute value and click Next.
12. Click Finish when registration is complete.
13. Restart the AD FS Windows service. This is required.