When attempting to open FTK/Lab/Enterprise, a new window pops up with an error message stating that the system or server is busy and gives you the options to "Switch to" or "Retry".
Open the firewall port 5432 between the FTK client and PostgreSQL database. The commands below can be run through a command prompt to accomplish this.
netsh advfirewall firewall add rule name="AccessData PostgreSQL" dir=in action=allow protocol=TCP localport=5432
netsh advfirewall firewall add rule name="AccessData PostgreSQL" dir=out action=allow protocol=TCP localport=5432
This issue is caused by communication being blocked by the client (FTK) and/or server (PostgreSQL).
NOTE: the port value will be different than 5432 if during FTK installation, a non-default port was selected.
Note: If the above is not helpful, then here is a help article describing other possible causes.