If you are importing grades into the virtual classroom copied from Excel and it returns an error, some of the possible causes are:

• The grades you copied from Excel are not formatted in the proper format: if there are decimals, make sure you used a dot as a separator, instead of the comma.
• In the last step of the import, you indicated that the column where the NIUs appear in Excel should correspond to the field ID Number – not to be confused with User ID.

Find all the information step by step at the post How to easily and quickly publish notes from Excel.