Could this problem be related to my computer crash and the recovered files?
Very easily. The indexes of your files may not be in good working order. And there might be other ways that a "post crash" file might fail.
A crash can damage files and damaged files can crash.
And while Recover usually can both detect and fully repair the damage, there are no guarantees. Recover doesn't always detect damage to a file and recover doesn't always succeed in fully repairing the damage it does detect.
Your best bet is to take a back up copy made before the crash, save a clone of it and then import all data from your recovered copy into this clone of the file and use it in place of what may be a damaged file.
I was excited to get your comments and when I came into the office this morning I cloned a file I had backed up on a CD from 2010 ... well before my computer crash and thought I would have solved the problem ... but NO! But, I'll try again with another file (perhaps one in FM 12) as the one from 2010 was FM 7.
Thanks for your suggestion.
Note that sometimes the data in a field can appear to be a duplicate of the same value in the other field when it is not. The presence of a space after the last character in one field that is not in the other record's field is one such example.