I had a situation where I canceled an on-going Pulumi operation (at the time, I could not find where another process was running), and now while I can update existing resources, whenever I add any resource with any name I get: "Duplicate resource URN '<the name>'; try giving it a unique name" - so I'm assuming something is corrupted. Is there any action to take to investigate further? Thoughts on how to proceed?

I don't think that can be caused by bad state. The engine only errors about duplicate resources for when the same name is registered twice by the program, so I'd guess you must have introduced a bug in your program where your now trying to create the same resource twice, or two different resources but with the same name. Often the later is due to component resources, names are globally unique, not unique per-parent so component resources generally have to prepend their name to the child resources names to keep everything unique.

And you would be correct - it happened even when I changed names - but you are correct, I was trying to create everything twice without a prefix. It might be nice to explicitly call out that there are two new resources in the error message, but not a big deal. Thanks for the help!