(2020-02-12, 23:24)Alastair W Wrote: Many thanks for your help, I've solved the problem..dat and .ldr are just hints concerning the generic purpose of the file. Both are LDraw, so you can just rename the file to .ldr if studio hasn't got a 'all files' option in it's import dialog.
I opened the .dat file in MLCad and then saved the part as a .ldr file which I could then import into Studio.
I also found that I had to update the parts in my Studio install which I did from the complete.zip.
ps: Also Studio uses the LDraw format (hidden in a zip for model files) and library so technically you aren't even importing just copying.