It sounds like you're just in "Page Break View" if you're seeing grey space
next to your last column. All the columns to the right are still there, but
in page break view if there is nothing in them, they don't show. Just go to:

ViewNormal at the top file menu bar.

"rosebud3377" wrote:

I was trying to get rid of the contents in the columns to the right of my
spreadsheet and instead I accidently deleted everything to the right. Now I
can't insert new columns because I have limited the size of the spreadsheet
(just grey space to the right of my last column). How can I recover columns
to the right? I can't just click undo because I have saved and gone out of
the spreadsheet.