EnumComPorts is not fully compatible in Unicode Delphi Versions.
It calls RegEnumValue() which retuns the length of the data in Bytes in DataLen.
The it uses the DataLen in a call:
SetLength(Data, DataLen - 1);
This only works in non-Unicode, as SetLength wants Characters, not Bytes. The resulting String will be twice as long in Unicode, with trailing garbage as the data is uninitialized.
SetLength(Data, DataLen div sizeof(char) - 1);