There are many factors that can affect the performance of Attaché Pro.
Below are some actions you can take to potentially improve the performance of Attaché Pro:
Restart the server where Attaché Pro is installed.
Restart the affected workstations.
Whitelist the Attaché Pro folder on the Anti-virus and Firewall.
Ensure the network has an adequate speed.
Ensure the workstation is not using all the resources on Task Manager when running Attaché Pro.
Re-map the network drive where Attaché Pro is installed.