Here is a list of safety principles to follow to ensure that your SuperMemo databases are safe and sound:
1. exit SuperMemo before turning off the computer or before starting an application that might cause an unrecoverable system lock-up
2. keep 2-3 back-up copies of your database files (particularly, after adding a larger number of new items). Do not back up files of an open database!
3. in case of abandoning the program in a prohibited way, e.g. in power failure, use Tools : Recover to check your databases for integrity, or use your database back-up copy
4. never try to modify the content of database files by means of tools other than those supplied by SuperMemo World
5. run Tools : Garbage once every few months (set the Compact check box on, if possible), and Tools : Recover at least once a year
6. keep accurate date and time setting
7. if Database integrity error message appears, (1) create a back-up copy of the database (do not override earlier back-ups), (2) run Tools : Recover and (3) run Tools : Garbage (set the Compact check box on, if possible)