Issue
Nintex Form displays blank when item is edited.
Resolution
If a SharePoint column contains illegal characters or non printable characters it may cause an issue opening a Nintex Form for editing.
For example, if you copy a table from Excel and paste it in a Multi Line Textbox (Enhanced rich text) and save it, you may have an issue opening that form because it may include illegal characters or non printable characters.
For resolution, click edit in the SharePoint list (or click "Quick Edit" button in the list ribbon) and clear the data in the Multiple lines of text column.
For example, if you copy a table from Excel and paste it in a Multi Line Textbox (Enhanced rich text) and save it, you may have an issue opening that form because it may include illegal characters or non printable characters.
For resolution, click edit in the SharePoint list (or click "Quick Edit" button in the list ribbon) and clear the data in the Multiple lines of text column.