Did some searching and found some suggestions, but none of them works. I have a BP that at some point in the past contained function (or was it a macro?) DoSomething. After rearranging the code DoSomething became obsolete, so I deleted it. Some time after that I had a problem saving BP, UE displaying a message that it “can’t save blah blah” and naming DoSomething as a culprit but File/Refresh all nodes helped. Now I have duplicated the BP, to test other approach - did some changes to the code, and I can’t save the new BP for exactly the same reason. Searching the BP for DoSomething doesn’t find anything, refreshing nodes doesn’t help.