Run the following against your database to find all of the columns that have a datatype of varchar:
SELECT table_name [Table Name], column_name [Column Name]
FROM information_schema.columns where data_type = 'varchar'
If you find them in custom tables, you can change the datatype of the column to nvarchar or exclude them from the data model regen via
To exclude the table you need to:
1. Exit from the Epicor Admin Console.
2. Make a copy of the configuration file Ice.Tool.DataModelGenerator.UI.exe.config first and call it Ice.Tool.DataModelGenerator.UI.exe.config.bak.
(The config file is located here for 10.0.7xx versions C:\Program Files (x86)\Common Files\Epicor Software Corporation\Database Manager Extensions\3.0.7\DataModelGenerator\Ice.Tool.DataModelGenerator.UI.exe.config).
3. Edit the original configuration file by adding it to the ExcludedTables section of the configuration. In the example below table Erp.HelloWorld was added to the exclusion list.
<setting name="ExcludeTables" serializeAs="String">
4. Save and exit.
5. Launch the Epicor Admin Console
6. Run Regenerate Data Model for the database in question.