I occasionally have to repair a table - I usually notice this requirement when trying to change the default field data; restructure won't work until the table has been repaired. However after my recent experience I would like to recommend that before rebuilding a table, you should backup the corrupted table - obviously to a different location to your normal backups - because if the rebuild fails it is possible to do even more damage.
Usually when I repair a table I just let Paradox rumble happily away until it is finished but yesterday when I started a repair, I opened a new window and began working with another program. In the past, I have always left the Paradox screen open until the repair had finished but when I returned to Paradox this time I discovered that the program had hung. I used Task Manager to end it, then reloaded Paradox to discover that all my filters had disappeared, my default fields were all empty and four records out of 120,000 had vanished completely. Presumably, these were the records Paradox was actually working on when the program hung.
Fortunately, the table was backed up immediately before the repair and after copying it back and starting the repair again everything worked perfectly. But because of this I would heartily recommend:
1) Backup the table immediately prior to the repair.
2) Don't run anything else while Paradox is repairing.
I'm using Paradox 10 under Vista.