Why do one or more reports display slowly or stop responding?
Most reports return results within a few seconds to a minute. Some reports might take longer if the report includes a large number of records, or if the system usage is high.
If you are a user:
Edit the filter before you run the report to select fewer records.
If you need to run a summary report for a large number of records, such as the Account Distribution report, expect it to take a while to run and try to run it when system usage is low.
If you are a system administrator:
Change the default filter on the report to be more restrictive.