I wish to convert a number of old schematic files created by Circuitmaker 2000 (*.ckt) so I can edit with Multisim and layout with Ultiboard. Does anyone know or can advise of a method to convert into a format I can use to import into Multisim?
Unfortunately Circuitmaker schematic files cannot be imported into Multisim. But if you're looking to import a SPICE netlist from Circuitmaker for simulation in Multisim, you could definitely do that (See this tutorial: How to Import a SPICE Netlist for Simulation in Multisim). To export the SPICE netlist from Circuitmaker, choose File > Export > SPICE Netlist. I wasn't able to find whether or not Circuitmaker could export to Orcad format, but if so, you might be able to import schematics (but not simulation models) that way.
In terms of layout files, Ultiboard can open some of the export formats supported by Circuitmaker, however it is suggested that you download the evaluation version first to determine how extensive the support is, especially considering there will be multiple conversion steps involved here. The formats that Ultiboard can open that Circuitmaker can export to include Protel, Orcad, PADS and Calay netlists. But once again, it is highly suggested to test out how extensive the support it considering the double-conversion, and to account for differences in versions supported.