I am getting this error message for one of the columns in my big table:

Question

FOR XML could not serialize the data for node 'NAME' because it contains a character (0x001A) which is not allowed in XML. To retrieve this data using FOR XML, convert it to binary, varbinary or image data type and use the BINARY BASE64 directive.

Answer 1

The message is fairly clear: it is simply the case that some characters are not permitted in XML.
Character 0x001A is 26 decimal and this is a control character and if you have this in a column called NAME there is something spooky with your data, and there is reason to investigate this:
SELECT * FROM tbl WHERE charindex(NAME COLLATE Latin1_General_BIN2, char(26)) > 0
If you don't care, you can wrap the troublesome column replace:
replace(NAME NAME COLLATE Latin1_General_BIN2, char(26), '?')
The binary collation is required since char(26) is typically an undefined character in a Unicode non-binary collation and unexpected things happens.
Erland Sommarskog, SQL Server MVP, [email protected]