Error when adding new deck

My anki collection has lots of cards already, but I wanted to add another deck.
However, when I try to add this deck, I get the following error:

Import failed. Debugging info:
Traceback (most recent call last):
File “aqt\”, line 404, in on_done
File “concurrent\”, line 432, in result
File “concurrent\”, line 388, in __get_result
File “concurrent\futures\”, line 57, in run
File “lib\site-packages\anki\importing\”, line 44, in run
File “lib\site-packages\anki\importing\”, line 41, in run
File “lib\site-packages\anki\importing\”, line 64, in import
File "C:\Users\Savage Unicorn\AppData\Roaming\Anki2\addons21\1102281552_init
.py", line 72, in newImportNotes
shouldAdd = self._uniquifyNote(note)
File “lib\site-packages\anki\importing\”, line 189, in uniquifyNote
File "C:\Users\Savage Unicorn\AppData\Roaming\Anki2\addons21\1102281552_init
.py", line 255, in _mid
File “lib\site-packages\anki\”, line 231, in update
File “lib\site-packages\anki\”, line 414, in add_or_update_notetype
File “lib\site-packages\anki\”, line 265, in _run_command
anki.rsbackend.InvalidInput: InvalidInput { info: “attempt to save stale notetype” }

If I add the same deck to an empty new anki profile, there are no problems. So I am assuming something is conflicting with the currenty profile / cards I have.
Can you help me figure out what may be wrong?
Thank you.

4 posts were merged into an existing topic: Special Fields error on 2.1.30