When attempting to open FTK/Lab or perform various actions in the application, a Windows error will appear with the error message below:
"This action cannot be completed because the other program is busy. Choose 'Switch to' to activate the busy program and correct the problem."
Note: Consider setting exclusions for the database engine port (e.g. port 5432 for Postgresql) in any firewall application (e.g. Windows Firewall). If the "server busy" error still persists after exclusions were added, then see the following resolutions.
1. Disable the Revocation Checking Policy either locally or on the domain using the article linked here.
2. Upgrade to .NET Framework 4.0 or newer
3. Change the Revocation Settings through Internet Explorer settings:
The issue may be experienced on systems that are not connected to the internet and/or have an old version of .NET Framework. The application is attempting to verify the signature on specific .NET libraries used by FTK/Lab and may not be able to access the revocation information through the internet. .NET Framework 4.0 and newer versions do not exhibit this same behavior.
This issue was observed with AD Lab 5.3 in an "offline" environment.