After you choose File : Repair collection, before the system check-up and recovery begins, the Recovery Options dialog box appears on the screen.

The recovery options are as follows:

• Basic recovery - quick integrity checkup of the learning process in the current collection
• Rebuild registries - if you check this box all registries in the collection will be rebuilt and compared with their old versions. All differences will be reported as errors. This process takes pretty long therefore you will want to go through it only if you experience some serious registry problems or you prepare your system for release and want to make sure that its integrity is impeccable
• Verify tasklists - if you check this box, all task elements will be verified. SuperMemo will check if the associated task exists on the relevant tasklist and that the tasklist has not been deleted
• Verify filespace - if you check this box all files in the secondary storage (i.e. elements folder) will be checked for their names, numbering, duplicates, empty filespace slots. etc. If you have made a mistake in backing up the elements folder or you experimented with manual merging two versions of elements folder from two different versions of the same collection, chances are you have introduced some integrity problems in file naming. Integrity of the filespace is also often disrupted by adding new file objects while being disconnected from the secondary storage or with a wrong secondary storage setting (e.g. after changing a CD-ROM drive letter in Windows). In the latter case, SuperMemo will move all occluding files to new slots to restore full integrity of the filespace
• Rebuild lexicon - if you have done lots of lexicon editing and would like to revert to full lexicon, you can compile the lexicon anew by checking this box. You may also want to use this option if you unchecked Compile lexicon on the fly and your lexicon is not complete. On the other hand, this option can dramatically increase the time of recovery if your collection is jam-packed with long articles on your reading list (e.g. as collected from the Internet)
• Verify translation - you can use this option to make sure that your translation registry is properly sorted and that all text components in the collection are translated or reported as having translation missing

To perform a quick checkup of your learning process, do not check any boxes among Recovery Options. On the other hand, if you want to quickly perform the maximum checkup and recovery of the collection, choose Check all and then OK (uncheck Rebuild lexicon if your have lots of long articles on your reading list)