Maintenance Plan Wizard generates invalid date parameter in script for delete
It's not related to the date format, the generated T-SQL from Maintenance Plans doubles up the single quotes (') in the generated script. A double quote escapes a single quote inside quoted text.

For example:

SELECT 'Figure 1'


would return the value "Figure 1", whereas:

SELECT ''Figure 1''


Would throw an incorrect syntax error similar to yours.

When you extract the T-SQL for a Maintenance Plan task, you should copy it into a new query window and do a Find &amp; Replace to replace '' with '. You may have to run it twice depending on the generated script.