In case the guide can't assist, then firstly see following helpful topics
http://forums.techguy.org/windows-7/1135994-i-need-help-lotus-notes.html
http://itknowledgeexchange.techtarget.com/itanswers/corrupt-lotus-notes-nsf-file/
If your .nsf file severely corrupted, then I would advise you to see next method https://www.repairtoolbox.com/lotusnotesrepair.html Lotus Notes Repair Toolbox
Follow the given steps to resolve the error:
1) Restore the data from recent database backup
2) R fixup -f", then "compact -c -i" command to recover the corrupt database.
Note: If the inbuilt Lotus repair doesn’t help you to repair the corrupt database then, you require some alternative Lotus Notes Recovery software to repair and recover the corrupt database items.
