Re: Question: Performance issues when formatting netflow csv for export/download (McAfee Enterprise Security Manager 9.6.0)
You can open a ticket with Support to see if they can help.
Just make sure you only selected the datasource you are exporting logs from, remove the fields from Events view that you don't need in the query, select a narrower time window, export one page at a time if the Events view is more than one page, etc.; things like that will speed up the process.
Not sure if it makes a difference but I'd also try it in a different browser like Chrome or Firefox.