When attempting to simulate or compile a PLD file on WinCupl, I get the error:

Error '35602':

Key is not unique in collection.

after which the program crashes and closes.

What is the meaning of an error like this? A quick search brings up many questions (e.g., this, this, or this), but these all yield application-specific solutions. My scenario is also application-specific, but WinCupl is an old program and I can't find similar support online.

Some of the answers to those questions say something along the lines of: "This problem is caused by a key in a table of the database that is not unique." Can someone give some insight on what this means, and/or possible solutions to look into?

Note: I was thinking about posting on Electronics Stack Exchange, but this program doesn't seem to be commonly asked about on that site and I thought I might get a better understanding of the error here. If you think a different Stack Exchange site is better suited for this question, please flag/comment.

2 Answers 2


I had the same same problem and traced it back to a point where the tree in the project window is populated . I was able to work around it unticking Project under View on the Menu before compiling. Not sure if this will work for you but I spent hours looking for a solution to this so figured I'd share my experience.


I understand that some time has passed since the question was created, but I hope this will help someone else. I have the same error, but it occurred when I just opened the project. And so, as I discovered, the reason was the same file name (I copied the project file before some test changes to same-filename.pld.store). For some reason I had to close the project and WinCUPL, and when I tried to open it again, I got this error. The first thing that helped was to move the project file to another location. It opened normally. And then I moved the copy file to another location, and returned the project file back. And it opened normally again. Returning a copy to the old location and the project returns an error again.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.