When opening an application via 4D remote client, an error message may be encountered that states:

-10521 | Can't open database {application_name} because it's not in Unicode mode.



This may occur when the application is converted from a previous version using 4D Server. When first launching it, a prompt may appear to ask to temporarily switch to Unicode mode:



Even if "OK" is selected, to prevent remote clients from encountering error -10521, the "Unicode mode" option must be manually enabled in structure settings on 4D Server.