OE6 Switching Identities - lost emails

I have set up separate "identities" within OE6 for my wife and my son, in addition to the main identity (me). I have switched between identities without problem for several years ........until last week.

After switching from main id to wife's id then to son's id, I then attempted to switch back to the main id. Instead of the PC switching id's within a moment or two as usual, my wife's id version of OE6 closed and I was left looking at my desktop instead of being switched into the main id version of OE6.

As there was no further response after 5 minutes and I could think of no other way of getting into my inbox, I rebooted the PC. As expected it rebooted fine but, when I opened up OE6, I was presented with the inbox of my wife's id.

I then successfully switched into main id without delay.

HOWEVER, all the emails which had been in the main id inbox had disappeared and I cannot trace them.

Can anyone suggest what may have happened and how I may find these missing emails?

Thanks if you can.