I use Unique IDs most of the time and have no problems. But i am currently working on a tool where i have to convert from Element IDs (the short, unstable ones) to Elements (ideally so i can then get the UniqueIds moving forward). See attached Image. Is there a problem with the Clockwork Node that prevents it from using Element IDs? Ive tried converting the ID to a string and still have no luck.
The built-in Element.Id node doesn’t return actual IDs, instead it converts them into numbers. Clockwork’s Element.ByID node expects a real ID (which you can obtain by using Clockwork’s Element.ID node) or a UniqueID (which is always a string). I was too lazy to include some functionality that would also obtain an ID from a number. I should probably get around to doing that at some point. 
If you have your IDs as numbers you should use Konrad’s Id to Element node from package archi-lab.net - he was less lazy… 
Thanks for the explanation Andreas. I think I’m going to have to use Konrad’s node since the IDs I have are coming from an HTML report from Revit - hence they are only txt values.