That's how strings work, unfortunately. You can't end any string (raw or not) with an odd number of backslashes. You could do the following to get around this limitation:

>>> r"C:\Folder" "\\"
'C:\\Folder\\'

As a side note, please don't upload screenshots if what you're capturing consists only of text (you can paste it directly in your message). This makes it impossible to copy-paste input in the interpreter to try to replicate the issue, and makes it harder/impossible for the blind and visually-impaired to contribute. Thanks!