When selecting data from a table with over 80 columns of varchar2(4000) type, the following error appears immediately, when running the statement with F9:
'Access violation at address 0000000004C3C103 in module 'Toad.exe'. Write of address 000007FFFFF4B0FC'
With F5, the statement runs.
Please set the OCI Array Buffer Size setting in Toad to 'Auto', so it can be managed by the application.
This can be found in the menu: View | Options | Oracle | General | OCI Array Buffer Size