Backing up the learning material


Safety of your knowledge stored in SuperMemo

Knowledge you store in SuperMemo might belong to your most precious data on your hard disk! After all, it has cost you months or years of editing and repetitions. You must continue your repetitions indefinitely to make sure you do not forget what you have learned. This is why your skills in making a backup copy are so vital!

Everyday you should pause for a moment and imagine the consequences of losing your work since you made your last backup.

In SuperMemo you can backup your collection with File : Copy collection (e.g. when you want to choose a specific location on your disk where the copy should be located) or with File : Tools : Quick backup (e.g. if you want to back your collection up often at a specific location with a time stamp). See below for details.


To prevent losing your collection (e.g. to a disk failure), you should make regular copies of that collection (e.g. on a flash drive). Such a copy is called a backup and making it is called making a backup.

If you lose your collection (e.g. to a disk failure), you can always get it back from your backup. This process is called restoring the backup.

It is much easier to handle collections for backup if you put them into a single file. This process may be called packing, zipping, archiving or compressing in the documentation of the program used in combining collection files into one (e.g. WinZip, Total Commander, etc.). Compression used in archiving is lossless by default (this means you do not lose data, only reduce its size).

Check your backup!!!

Remember to retrieve and review your backup from time to time to make sure your backup files are stored correctly! Some users backed up only their KNO files for months thinking their backups are safe and complete!

Copy collection

Use File : Copy collection (Shift+Ctrl+C) to copy your learning material to some new location. You should copy to a different computer, to a flash drive, or to a DVD-R from time to time to prevent losing your work in case of a hard disk crash. If your collection is named Physics and you choose File : Copy collection, SuperMemo will suggest a new name Physics (copy). If you accept that name (e.g. by choosing OK or pressing Enter), a copy of the collection will be created at the same place as the original collection with the name expanded by (copy) (e.g. Physics (copy)). However, this backup is useful only for cases such as a software crash that might damage the original collection. This copy is not safe from a hard disk failure (it is located on the same disk), and is not safe from a virus attack (that might wipe out or scramble the entire folder with your collections). This is why you could at least change Look in field in the file browser to select another drive to make your copy.


To backup your collection to a network drive named F:, you can press Shift+Ctrl+C, type "f:\my_July5_backup" and press Enter. Naturally, it would be nicer to backup to a dedicated folder, e.g. "f:\SM15\backup\July5".

Quick backup

To prevent losing your collection (e.g. to a disk failure), you should make regular copies of that collection (e.g. on a flash drive). Such a copy is called a backup and making it is called making a backup.

The fastest and simplest way to make a backup is to use Quick backup in SuperMemo as described below.

Making a quick backup

The fastest way to quickly backup your collection is to use Shift+F12 (or File : Tools : Quick backup). Quick backup will skip non-essential files (e.g. temporary files). It will also name your backup with the date on which it was created. For example, if your collection's name is YouTube.kno your backup might get named (((Backup of YOUTUBE created on 2009-05-28 15-15-55))). This name tells you that the backed up collection's name is YouTube, and that the collection was backed up on May 28, 2009 after 3 pm (exactly at 15:15:55 on the clock).

SuperMemo: The YouTube collection to be archived at at c:\dvd\colls\youtube folder

In the examplary picture above, the collection YouTube will be archived in the folder c:\dvd\colls\youtube\

SuperMemo warns you if you open a quick backup

In the past, users often made a mistake of learning with their backup, instead of their original collection. To avoid this confusion, SuperMemo will warn you each time you try to open a backup collection.

You can easily eliminate that warning by renaming the backup collection. Always rename the collection to its original name when you restore a backup. For example, if your collection's name is YouTube.kno, and your backup is named (((Backup of YOUTUBE created on 2009-04-28 15-15-55))), name the collection back to YouTube.kno or similar at the time when you restore the backup.

Restoring a quick backup

If you lose your collection (e.g. to a disk failure), you can always get it back from your backup. This process is called restoring the backup.

You can restore the backup by opening the backup collection with File : Open collection (ignore the warning), and using File : Copy collection (Shift+Ctrl+C). You should then copy the backup to your collections folder within the SuperMemo folder (e.g. c:\sm15\systems\), and give it the name of the original collection (e.g. c:\sm15\systems\YouTube.kno).

Where shall I put my backup?

Remember that the safety of your backup depends on its location. Here is a short list of examples from the safest to the least safe:

  • backup on different media on different continents (e.g. flash drive in America, DVD in Europe, Internet server in Asia, etc.)
  • backup in a different city (e.g. on a friend's computer)
  • backup on different media in the same location (e.g. DVD in the same office might be vulnerable to office fire)
  • backup on a flash drive (might be vulnerable to theft if the flash drive is placed in the same computer as the collection)
  • backup on another hard disk (might be vulnerable to power surge, fire or flooding that will damage both disks)
  • backup on the same disk (may be lost at any minute due to hard disk failure)
  • backup in the same folder (might be deleted accidentally when deleting the folder)

Conclusion: always keep your backup as far away from your collection as it is feasible and reasonable.

If you need to back up on the same PC, keep the backup on separate drives, e.g.


Backup:C:\backups\supermemo\collections\(((Backup of YOUTUBE created on 2009-04-28 15-15-55))).kno

Using WinZip, PKZip, etc.

If you would like to use archiving tools to reduce the size of your backup and keep it in a single file, remember to do the following:

  • copy the file <your collection>.kno and the folder <your collection> into one archive. Many users make a cardinal mistake of archiving only the kno file which is useless without the files in the accompanying folder. For example, remember to copy the folder BIOLOGY-CLASS when backing up biology-class.kno
  • remember to preserve the paths in archiving. If you fail to do this, you will most likely be unable to reassemble hundreds of files into appropriate folders

Learning process backup

For advanced users: If you are using a commercial collection available on CD or DVD, you can save lots of space if you backup only the learning process. You can do it with File : Export : Learning process. Note that this will not preserve changes you have made to texts in your collection. In case of a mishap, you can reinstall your commercial collection and restore the learning process with File : Import : Learning process : Text file. For example, the full semi-copy of Advanced English takes nearly 50 MB while the learning process backup takes from 0.1 to 3 MB depending on how much work you have put in repetitions.

Example: Archiving with Total Commander

To archive your Physics collection with Total Commander by Christian Ghisler do the following:

  • find physics.kno (e.g. with Alt+F7 search)
  • in the panel displaying physics.kno, select physics.kno and [PHYSICS] folder (e.g. with Ins or with Ctrl+click)
  • choose Alt+F5 for Files : Pack...
  • make sure Also pack path names (only recursed) and Recursively pack subdirectories are checked (to preserve paths and folders)
  • choose OK.

Your newly created archive should appear as a ZIP file with the default name <collections folder>.zip (this is by default)

Further reading