It sounds like a folder sharing issue and not related to the All-in-One, but it’s impossible to know without seeing your exact computer setup.
Here are two possible solutions:
- First, try downloading a fresh version of the model from your ‘My Downloads’ page. And then change the file name once it has been saved to your computer. Once the file name has been changed, open the file, make a few changes, and then attempt to save again.
- The second possible reason for this issue is that there’s a file permission/read-only issue. Here’s a video with a possible solution to that issue: