Hi Steven,
Thanks for sharing your experience here and we will try our best to help you.
According to your description, it seems that the password didn't work in a protected document and there is an issue related to backspace feature.
We would like to inform you that backspace will only be worked once time if you press it which is expected behavior. Or could you share the detailed description of how it should work at your end?
To help us better understand your situation, for the "return key" issue, could you share the following information when you have time:
- As you mentioned, then return key no longer work, if it means that you can open this protect document without a password?
- What OS you are using? Windows or Mac?
- What Office product you are using and What's your current Office version?
The information is very helpful to us to troubleshoot your issue, appreciate your efforts.
Best Regards
Higgins