A manual FULL backup of Exchange, SQL, or MySQL must be ran initially to ensure the success of the following incremental or differential backup jobs.
Exchange and SQL backups have two schedules by default. One for the database, one for the transaction logs. The database backup (runs on Friday by default) is a prerequisite to the transaction log backup (runs on Tues-Thurs by default).
If you created the Exchange backup between 9pm Thursday and 9pm on Friday (again these are the defaults) you would be good. Otherwise, run a manual backup or alter the backup schedule (database today, transaction logs M-W&F).
Assuming you have already created the SQL or Exchange backup set, to execute a full backup manually, simply:
- Launch the backup client and click “Backup” in the left pane.
- Choose the correct backup set to launch from the drop down
- Select the settings as shown below (be sure the "In File Delta" setting is set to "Full")
- When you click “OK” the backup job will run (shutting down SQL or Exchange is not required).