memo field

[CDAY]

5.0.13   XPpro

I have created memo field, imported data from an Access file 
into the memo field.

When I try to update or change data in the memo field the 
changes are not recorded. When I press F10 to save, the 
boxed memo display area disappears, if I press F10 again, it 
reappears.  If i move to a different record, then back to 
the reord changed, the changes are not saved in the memo field.

What am I doing wrong ?

Charles Day