Exception occured
 

Sometimes, randomly, when I launch my UserForm I get Exception occured
and I have to close the application. What kind of error is this? There is no
further explanation or error code. I've read at Microsoft Support that an
Exception occured may happen if one of more cells in an array contains more
than 911 characters.
I have only two arrays connected to my Userform, the first with 28 cells
with 50 characters each, the second a Userform textblock containing about 300
characters.