Amazing! I was struggling with MDS v1.0 as the example programs would not compile properly. I suspected the same paths issue described in this thread. I have now setup MDS 2.0 on my Macintosh SE with System 6.0.8 and MDS works exactly like it did back in my Uni days! My SE has a hard drive. I put the 3xMDS 2.0 disk images on my FlopppyEMU. Create a folder called ProgrammingTools in the root of your hard drive and copy the contents of all 3 x MDS v.2 disks into that folder. I then ran the MDS Paths Manager program using the provided Relative.Path file. The process will automatically configure the correct paths for you in a file called Paths.rsrc. Without this step you wont be able to compile a program correctly as the paths to the key MDS files will be wrong. Save the output file called Paths.rsrc from the Paths Manager to the root of your hardisk. Thats bascially it. To test, open the Sample.ASM program in the examples folder with the MDS editor. To generate an executable file that will run on your MAC, Click Transfer, then Assemble, Link, Exec and Rmaker the Sample.ASM file. All the example programs compile and run perfectly. The MDS 2.0 supplement.pdf Crutch provided in this thread describes it all perfectly. Thanks so much Crutch! Finally I got MDS v2.0 working with your amazing help! Thank you friend!