If you are having issues with the performance of your grade book in Infinite Campus try deleting your temporary files/cache.
You may also need to clear your temporary files if you are having trouble accessing your webmail.
You might have to close your browser before the settings go into effect.
Clear temporary files/cache with Safari
1-Click "Safari", then click "Reset Safari"
Clear temporary files/cache with Firefox
Clear temporary files/cache with Internet Explorer
1-Click "Tools", then click "Delete Browsing History" OR hold the Ctrl + Shift + Delete keys
2-Check the appropriate boxes, then click "Delete"