SuperMemo problems after hard reboot

Question:

Adrian: I'm running the most recent WindowsXP. I was listening to iTunes at the same time (which is quite unstable in my experience) and the PC froze; I had to do a hard reboot.

This is an unpleasant but *not unusual* situation for Windows users...! Fine. So when I rebooted SuperMemo had:

• forgotten I was registered (I had to re-enter my key)
• somehow lost my current knowledge base (I luckily had a backup that I could reload)
• had in any case forgotten the scores I'd already given myself until the PC froze

I am a programmer myself and I can't see why even a Windows crash should be able to wreak such havoc on SM "just because" of a fatal error with the operating system. I'm not sure how the whole knowledge base could just disappear (I have only one). This really scares me!

Is this a known problem with SM? How is it "supposed" to act when such a crash occurs?

Follow-up:

'Adrian: OK, I found a reference to exactly my problem on your web site. It looks like 'copy collection' and 'repair collection' are two things.

Answer:

• not being registered after the crash is not ususual, as with all crashes, the program sometimes does not get the chance to write data to the disk
• losing the entire collection as a result of a crash is unlikely. It could, for example, happen as part of a general wipeout of data on the hard disk, but then it would rather be accompanied by many other problems with many other applications. A far more likely explanation is that the collection has just not been added to the file pick-list (bottom of File menu). All you need to do is use File : Open and go to the location you created the collection
• learning progress is written down to the collection as soon as you move to the next element. This way only the currently executed repetition is wiped out on power down. Errors in data (e.g. last repetition day) could give you an impression that some learning has been lost. But this is easily fixed with Repair collection

All in all, SuperMemo loses far less data during computer crashes than applications that keep data in memory. If the crash occurs in-between repetitions, no data will be lost and no recovery is needed.

Losing your entire collection is always possible (e.g. virus attack). However, with a regular backup, you will be able to safely continue learning for many happy years.