STEPS TO REPRODUCE
1. Create an Nsql query using the following;
12345 as A123,
(2) as AAAA,
to_CHAR(-2) as BBBB,
-1 as CCC
2. Create a Grid portlet using the Query created in step 1 as the data provider and add all columns in the List Column layout section
3. Put the Portlet in a Tab on PPM => Home => Overview page and do an Export to Excel (Data Only)
Data gets exported to Excel and file opens up successfully
Excel file generated errors with message - 'This file cannot be opened because of errors'
This is reported as Defect DE46400
Resolved in Clarity 15.6 and back ported to 15.5.1 (Patch 1) 188.8.131.52
Do an 'Export to Excel' then save the output file again as a Comma delimited (CSV).