When importing Gift Attributes in version 4.7, some users have reported an error message beginning with the text "General ODBC Error: [Microsoft][ODBC SQL Server Driver][SQL Server]Conversion failed when converting the varchar value." (Note that the text following vachar value will depend upon your Gift Attribute setup.)
The issue arises when attribute values are blank in the initial row of the grid but are the populated later on. Importacular sets up the batch based on the first row but if the batch is not set up sufficiently i.e. because the later attributes have not been added, it will add an attribute when it first appears for processing.
However, RE for some unknown reason stores data at the end of the batch in the placeholders that we use for those later attribute values. When our team attempted to remove those extra data points the batch fails. This issue has been resolved in version 4.8 (which is set to release in Blackbaud hosting in Q1 of 2021).
The workaround is to either put those records in the first row of the file or import the file but then import those exceptions later. You should always try to use a first row that has the most populated attribute data.