We find this happens when usernames and the user's names contain special character(s) and/or non-English letter(s).
We have corrected this issue in our NumXL Version 1.64, which is set to be released soon. For now, 1.63 users can bypass this issue by completing the following list:
- When installing, make sure that the install for everyone is checked and that the computer account being used has administrative permissions.
- After installing you will need to check the NumXL Toolbar and NumXL boxes in the add-in manager. Information on how to do this can be found here: How to Find Your Excel Add-in Manager