I am not an expert & do not pretend to be so. I try to help where I can. I've been using LW for 4-5 years. Deleted my prefs many a time, sometimes just to experiment for users such as you on the forum. But I have never seen that problem immediately after deleting my lw prefs folder.

I can assure you , since I almost ONLY search for "rare" files, if my incomplete files become corrupt because I accidentally jumped back a version or whatever, I try to move on. Put it down to experience. As frustrating as it might be. Besides, if you've had LW for longer that 18 months, the due to the changes within LW, there would have been incompletes you would never have been able to resume anyway.

Sorry if my suggestion caused you problems & havoc, etc. But it was the most obvious suggestion to make. You could always buy pro & ask their support. I'm sure they'd know better than me.