I'll reply to my own post here... I finally figured it out after days of
frustration. Unknown to me, I had another program that was using the
CTRL-SHIFT-ENTER as a shortkey for something else. Every time I tried to
enter an array formula (unsuccessfully), I was actually triggering another
operation in the background. I turned that off, and now array formulas are
working perfectly again.

"erikheath" wrote:

I can't seem to use array formulas. The problem is when I am finished
editing it. I'll hit CTRL-SHIFT-ENTER and nothing happens; the screen just
blinks and the cursor stays in the formula bar. Could it be that there's an
option somewhere to disable these? I've been pulling my hair out for hours
trying to figure out why this isn't working and cannot seem to find a case of
anyone else having this problem.

Also, I've used array formulas quite a bit in the past and am positive it
has nothing to do with the formula or the way I'm hitting the
CTRL-SHIFT-ENTER command. To double-check that I'm not crazy, I've even
copied examples from Excel's Help sections, and they still won't let me use
the CTRL-SHIFT-ENTER command.