When importing a file into Clear Books for the first time, the columns of the file must be mapped to the data fields in Clear Books. This mapping is saved for future imports. If the layout of the file changes in future this could cause a conflict and prevent the file from being imported, therefore the mapping would need to first be deleted.
Navigate Tools > Import > Import mappings.
Select the dustbin icon beside the import tool mapping to be deleted.
Once the mapping has been deleted a file with a different layout can be imported and the mapping set accordingly.